Recommended Dietary Intakes - Do You Need Supplements?

By Paul Rogers

Here’s a quick definition of RDIs — or RDAs as they are called in some countries.

Recommended Dietary Intakes (RDIs) (or allowances, RDA) are the levels of intake of essential nutrients considered, in the judgment of national health and nutrition authorities on the basis of available scientific knowledge, to be adequate to meet the known nutritional needs of practically all healthy people.

RDIs are given for vitamins, minerals, protein and some fats, and for different life stages, and pregnancy, and are usually daily quantities. They represent the needs for sustenance and avoiding deficiency disease.  See examples for Australia and the US.

Now that sounds simple enough, but unfortunately the RDIs and other measures of nutritional adequacy are widely misunderstood. That definition above does not imply that the RDIs are the “minimum” quantity required to stave off malnutrition or starvation.

In calculating RDIs, a safety margin is used so that biological differences from person to person can be accommodated. It may be that some individuals have less of a margin than others, but overall, the RDIs and RDAs are designed to exceed the minimum requirements for just about everyone, significantly. The idea that they are minimum values finds great comfort in the vitamin and mineral supplement industry of course.

Optimising Diets for Chronic Disease Risk

 Even so, there is recognition that higher intakes may help prevent some chronic diseases. To be fair, this is likely to be where misunderstandings occur. For example, the RDI for vitamin C is 45 milligrams/day, yet the suggested target for reducing chronic disease risk is 220 milligrams/day — quite a difference. Folate is another example where the suggested dietary target or SDT is much higher than the RDI.

Other Standards in Nutrient Reference Values

Although terminology can differ from country to country, here is a full list of acronyms worth noting within the broad range of nutrient reference value (NRV) or dietary reference intake (DRI) standards as applicable in the US, Canada and Australia based on the Institute of Medicine proceedings.

• EAR (Estimated Average Requirement). A daily nutrient level estimated to meet the requirements of half the healthy individuals in a particular life stage and gender group.
• RDI (Recommended Dietary Intake). The average daily dietary intake level that is sufficient to meet the nutrient requirements of nearly all (97–98 per cent) healthy individuals in a particular life stage and gender group.
• AI (Adequate Intake - used when a recommended dietary intake cannot be determined). The average daily nutrient intake level based on observed or experimentally-determined approximations or estimates of nutrient intake by a group (or groups) of apparently healthy people that are assumed to be adequate.
• EER (Estimated Energy Requirement). The average dietary energy intake that is predicted to maintain energy balance in a healthy adult of defined age, gender, weight, height and level of physical activity, consistent with good health. In children and pregnant and lactating women, the EER is taken to include the needs associated with the deposition of tissues or the secretion of milk at rates consistent with good health.
• UL (Upper Level of Intake). The highest average daily nutrient intake level likely to pose no adverse health effects to almost all individuals in the general population. As intake increases above the UL, the potential risk of adverse effects increases.
• AMDR (Acceptable Macronutrient Distribution Range). An estimate of the range of intake for each macronutrient for individuals (expressed as per cent contribution to energy), which would allow for an adequate intake of all the other nutrients whilst maximising general health outcomes.
• SDT (Suggested Dietary Target). A daily average intake from food and beverages for certain nutrients that that may help to prevent chronic disease.

Dietary Supplements

Supplementation has a role to play, but it needs to be done with caution, restraint and knowledge. The bottom line is that there will be individuals and population groups that do not meet the RDIs for individual nutrients.

• This can result from poor nutrition practices or even special diets poorly implemented. Low-carbers could be short on fibre and vitamin E; vegans on zinc, iron and B12; and very low-fat dieters on long chain omega-3.
• Populations in nutrient poor regions might lack iodine and selenium; and certain cultural habits like full body clothing can result in inadequate vitamin D intake in the absence of food or supplement sources.
• Athletes and heavy exercisers may need a modest increase in some nutrients, but this is usually accounted for by increased calorie intake — as long as the extra food is nutrient dense for the most part.
• Older people absorb vitamin B12 less well and this may require supplementation. The ill or infirm who do not get adequate sun exposure may require vitamin D supplements.
• Pre- and during pregnancy, folate supplementation is a useful reassurance against neural tube abnormalities.

However, not only is it likely wasteful to take mega-doses of supplements, it may even be unsafe. The recent scientific examination of vitamin E and beta carotene in high supplement doses has not yielded promise and has suggested adverse effects. If you feel you need to take an individual supplement or a multi, first check out the excellent information at the Office of Dietary Supplements at the NIH. then try not to exceed the RDI by more than a few times for any individual nutrient, unless there are indications that it’s safe and effective to do so.

Burn That Belly Fat With High-Intensity Training?

By Paul Rogers

A recent study by researchers at the University of Virginia found that high-intensity exercise training disposed of more belly fat in obese middle-aged women than lower-intensity training of the same energy expenditure.

The idea that doing high-intensity interval training burns off stubborn fat and visceral belly fat has been around for quite a few years. The premise has always lacked strong evidence in my opinion — or at least reasonable qualification. Any number of internet training and fat-loss gurus are promoting this idea.

What is High-Intensity Training?

First up, we need to get the concept straight. What exactly is the ’interval training’ or ‘high-intensity training’ or ’high-intensity interval training (HIIT)’ that we hear so much about?

Interval training is intermittent training, often near your maximum, in which you do a lap of an oval, or a spin on a bike, or 60 seconds on a treadmill very fast, then you recover, and do it again several times. That’s simple enough.

For example, I’m a masters sprinter and in training I might do 10 x 100 metres at 95% capacity, or 10 x 40 metres at 100% capacity. This is high-intensity interval training in real life. But I’ve been a marathoner and triathlete as well (don’t ask), and high-intensity training for those disciplines is mostly entirely different; say, 2km fast, 2km slow, 2km fast; or 6 x 400 metres at 90% capacity, or even, I might add, 5km at race pace, which is still high-intensity training, even if not interval training. And further, I know that if you run 40 to 60 miles a week in marathon or triathlon training you’ll burn fat . . . lots of it. So what’s this HIT stuff all about?

Early Investigations Were Not Adequate

One problem with some of the earlier studies was that they did not set a rule for what constitutes ‘high intensity’. The study I quoted above used lactate threshold to determine this, an excellent idea. And few earlier studies actually compared the different intensities for the same energy expenditure, which is what needs to be done to get a reasonable comparison.

You can’t just do 6 spins on a stationary bike for 30 seconds flat out and expect to burn the same amount of calories and fat as someone who does 30 minutes on the treadmill at 85% capacity, or even a 90-minute run at slow pace for that matter. Energy expenditure, which just about always includes some fat and glucose burning, is going to be a product of intensity X time for any physical activity. 

In that event, the best approach for fat loss and fitness goals is likely to be a combination of interval training, weight training and cardio at different intensities. Big surprise eh? No, that’s right, it’s not. It almost reflects the recent exercise guidelines issued by the US government for general health and fitness.

Persistent Abdominal Fat and How to Shed It

What the study above suggests is that high-intensity training just might be superior to to lower-intensity training, for equal energy expended, in removing belly fat, especially the visceral fat wrapped around the internal organs that has been shown to increase your risk of heart disease and type 2 diabetes. Naturally, you have to include a nutrition program with some calorie restriction as well.

Even though the study involved a small number of women, 27, it seemed to be well designed. And yet men might respond differently, as might the young or post-menopausal women. It’s an idea that has promise for designing exercise programs for the overweight and people with metabolic syndrome and diabetes and is well worth watching in the future. The main problem is one that is not going to be easily solved: that unfit, obese people are unlikely to take on high-intensity training by themselves and stick to it, despite what you see on The Biggest Loser.

Having said that, there is plenty of evidence that aerobic, cardio type programs help people lose fat in general — even some visceral fat — and aerobic exercise has additional benefits for cardiovascular protection. A combination of weights, cardio and HIT is likely to be the superior program if it can be tolerated.

The Best Type of High-Intensity Training for Obesity?

Heavy people exert quite a shock to the knees when they run long or hard. It’s a real injury concern. Running is often out of the question for obese people, let alone high-intensity running. For this reason, I favour cycle spin classes on a stationary bike. Doing this exercise in a group has advantages. The instructor will encourage hard work, but it’s possible to set your own pace by adjusting resistance and peddle cadence if you get overwhelmed. You’ll get some high-intensity work threaded with lower-intensity cardio — an excellent workout combo. A medical checkup is highly recommended for anyone moving from a sedentary lifestyle to high-intensity training.

The Diet Wars Really Are Over

By Paul Rogers

John Tierney over at TierneyLab recently had a bit to say about the New England Journal of Medicine study that compared an American Heart Association low-fat diet with Atkins and Mediterranean diets.

I’ve discussed the details and the implications in a longer page post called Diet Wars, but the upshot of this and many other bits and pieces of nutrition research from recent times pretty much suggests that we stop wasting time debating low-fat or low-carb or in between and get on with recommending a healthy eating pattern that spans a wider macronutrient range for fat, protein and carbohydrate.

Let’s get the faddists, fanatics and false prophets on the run.

Does Stretching Work for Injury Prevention or Performance?

By Paul Rogers

If you’ve been involved in any sort of physical activity for fitness or sports, you probably know that ’stretching’ is highly recommended for the following reasons:

• Increase or maintain flexibility to prevent injury and increase mobility for day-to-day living
• Prevent injury during sports and exercise activity
• Increase performance in sport
• Offset muscle soreness after exercise

It seems to make sense doesn’t it? You feel that muscle let go and you think to yourself: “if only that muscle was a little more flexible, that would not have happened.”

The trouble is, much of the value of stretching got taken for granted over many decades and few scientific studies were undertaken to confirm what everyone assumed was correct: you must stretch.

Now, some of that scientific work on stretching has been done and it’s not quite as simple as logic would have us believe.

Maintain flexibility

To cut to the chase, stretching on a regular basis, perhaps daily, seems to be a good idea for everyone. Regular stretching probably has benefits for increased mobility, balance and injury prevention, especially as we age.

Prevent injury during exercise and sports

While regular stretching of various types may help athletes overall, stretching before or after an event or workout has mixed support for injury prevention, which I’m sure comes as a surprise to many. We all do it in some form because it makes us feel ready to compete. Benefits may be more psychological than physical. However, some recent review studies have been more positive, especially in relation to muscle-tendon injuries. Inadequate study design and confusion of the terms ’stretching’ and ‘warmup’ seems to have confounded much of the early science.

Enhance performance

Static stretching, it seems, may even impair performance in power sports like sprinting and jumping by interfering with optimum stretch-shortening cycle. It’s best not to confuse static stretching with warmups, in which dynamic stretching probably has a place.

On the other hand, some sports like gymnastics and dance require extreme flexibility and the same rules may not apply.

Overall, static, passive of PNF (proprioceptive neuromuscular facilitation ) stretching close to your sport or activity — before or after — seems to have little going for it in relation to performance benefit.

Prevent muscle soreness

Soreness after an exercise session is called ‘delayed-onset muscle soreness’ or DOMS. Stretching before or after exercise has long been recommended as a way to reduce or prevent soreness. However, a review of studies in this area did not find any benefit from stretching for the prevention of muscle soreness. Warming up is something different and has more calculable benefits.

Summary of stretching

In summary, the best advice seems to be that we maintain a regular stretching program from day to day, warm up sufficiently before exercise and sport, including some dynamic stretches — leg swings, arm swings are a good example — then warm down with some further stretches, but don’t expect that either performance or muscle soreness will benefit from static stretching at exercise time.

I’m certain this will be debated for many years to come.

- Small K, Mc Naughton L, Matthews M. A systematic review into the efficacy of static stretching as part of a warm-up for the prevention of exercise-related injury. Res Sports Med. 2008 Jul-Sep;16(3):213-31.
- Hart L. Effect of stretching on sport injury risk: a review. Clin J Sport Med. 2005 Mar;15(2):113.
- Herbert RD, de Noronha M. Stretching to prevent or reduce muscle soreness after exercise. Cochrane Database Syst Rev. 2007 Oct 17;(4):CD004577. Review.

How to Boost Immunity With Diet and Exercise

By Paul Rogers

How many times have you seen an ad for some wonder ‘erb or other that’s supposed to boost the immune system. It’s echinacea today and some Chinese herb the next, as well as a vast array of products that the supplement industry claim “support the immune system” — whatever that means.

Diet and Immunity

I’m not suggesting that diet and nutrition don’t have an important role to play in maintaining a healthy immune system. Meeting the recommended intake of macronutrients, vitamins and minerals and fats, and consuming copious quantities of antioxidant nutrients as part of healthy eating is bound to promote good immune system function — as far as it goes. However, the evidence for consuming individual dietary components or special foods or supplements beyond the RDI (recommended dietary intake) is mostly speculative or at least inconclusive.

Exercise and Immunity

If you follow a healthy lifestyle approach with healthy eating and a program of physical activity, here are a few things to note about how the immune system responds to exercise:

• A regular, low to moderate intensity exercise habit is associated with a reduced incidence of infection compared with those who do very little exercise or physical activity.
• Heavy, and or prolonged exercise training can impair the immune system, possibly leading to susceptibility to infection, particularly in a period of up to 24 hours after a heavy training session or event.
• Exercising at high intensity for prolonged periods without food — 90 minutes and beyond for example — may make you especially vulnerable to infection as a result of immune system depression.
• Consuming carbohydrate at the rate of 30-60 grams an hour during intense and prolonged exercise can help to maintain immune system function. That’s 1-2 sports drinks and hour or equivalent. (One drink is probably adequate for most situations except for extreme conditions and intensity.)
• Meeting your daily requirements for micronutrients like zinc, iron, and B and C vitamins is essential. Although a multivitamin supplement may help, consuming mega quantities of vitamins and minerals may be counterproductive. See article on Vitamin C and training adaptation.
• A recent review confirmed the value of carbohydrate supplementation and a possible role for vitamin C (note caution above), but no other supplement showed up as useful for heavy exercisers.

It’s worth noting the value of carbohydrate to immunity in a balanced diet and exercise program. Low-carbohydrate intake with low blood glucose, plus the stresses of exercise, increases cortisol production to the point where the immune system is compromised. Low-carb, high-fat diets, especially saturated fat, are not appropriate if you have a robust exercise program. In addition, saturated fat has been shown to impair immune response. Low-carb is not where you want to be if you exercise a lot.

J Sports Sci. 2004 Jan;22(1):115-25. Exercise, nutrition and immune function. Gleeson M, Nieman DC, Pedersen BK.
JEur J Clin Nutr. 2007 Apr;61(4):443-60. Nutritional modulation of exercise-induced immunodepression in athletes: a systematic review and meta-analysis. Moreira A, Kekkonen RA, Delgado L, Fonseca J, Korpela R, Haahtela T.
Scand J Immunol. 2008 Jul;68(1):30 42. Differential effects of a saturated and a monounsaturated fatty acid on MHC class I antigen presentation. Shaikh SR, Mitchell D, Carroll E, Li M, Schneck J, Edidin M.

Food and Fitness Science Roundup

By Paul Rogers

For this regular roundup, I try to find work that tells us something significant or new in the context of the field of study.

New Recommendations for Vitamin D Intake for Children from the American Academy of Pediatrics

A recommendation for a doubling of recommended dietary intake of an essential nutrient for any population sector is substantial news in nutrition science. The AAP list the reasons and the strategy here.

http://www.aap.org/pressroom/nce/nce08vitamind.htm

Coffee Drinking Does not Raise Mortality

Up to 6 cups a day and risks were still normal and even slightly lower than the consumers of much more moderate quantities. Adjustment of cardiovascular risk seems to be the difference — perhaps by lowering the risk of type 2 diabetes?

http://tinyurl.com/6al7ho

Ann Intern Med. 2008 Jun 17;148(12):904-14. The relationship of coffee consumption with mortality. Lopez-Garcia E, van Dam RM, Li TY, Rodriguez-Artalejo F, Hu FB.

Also see: Does Coffee Kill or Cure?

Red Wine Seems to Cut Risk of Lung Cancer

What? Not another reason to drink red wine! The authors do counsel against excessive consumption.

http://tinyurl.com/5u2wd3

Cancer Epidemiol Biomarkers Prev. 2008 Oct;17(10):2692-9. Alcoholic Beverage Intake and Risk of Lung Cancer: The California Men’s Health Study. Chao C, Slezak JM, Caan BJ, Quinn VP.

Vitamin C Interferes with Training Adaptation and Performance

I noticed the possibility of this a few years ago while researching the utility of antioxidants like vitamin C to benefit athletic performance. Vitamin C seemed to inhibit phosphofructokinase, which is an important enzyme in glycolysis (breakdown and use of glucose for energy). Considering that many athletes and fitness buffs seem to take vitamin C supplements, it may be worth noting. Moderate dietary intake is likely not a problem. We need more information on this one before the panic sets in.

Am J Clin Nutr. 2008 Jan;87(1):142-9. Oral administration of vitamin C decreases muscle mitochondrial biogenesis and hampers training-induced adaptations in endurance performance. Gomez-Cabrera MC, Domenech E, Romagnoli M, Arduini A, Borras C, Pallardo FV, Sastre J, Viña J.

http://tinyurl.com/5t85lh

Caffeine Plus Carbohydrate Increases Glycogen Storage

As far as I am aware, this is the first time this has been shown. About 500 mg caffeine is a lot of coffee though.

J Appl Physiol. 2008 Jul;105(1):7-13. High rates of muscle glycogen resynthesis after exhaustive exercise when carbohydrate is coingested with caffeine. Pedersen DJ, Lessard SJ, Coffey VG, Churchley EG, Wootton AM, Ng T, Watt MJ, Hawley JA.

http://tinyurl.com/6bwtv8

New Glycemic Index and Load Tables

If you’re into the GI, you’ll need this. More on the GI in another article. I’m not a big fan.

http://tinyurl.com/6flcjc

Click through to here from the abstract and you can download the free tables.

Diabetes Care. 2008 Oct 3. International tables of glycemic index and glycemic load values: 2008. Atkinson FS, Foster-Powell K, Brand-Miller JC.

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Check out the Food for Life, Fit for Life Training Program. Free download available.

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The Truth About Organic Food

By Paul Rogers

I’ve been a keen gardener most of my life, following a strong family tradition. We’ve grown everything from flowers and ornamentals to fruit trees and vegetables — with varying measures of success. Organic growing in a home garden, and wherever feasible commercially, just seems like sensible environmental management to me . . . and it’s especially applicable to home gardening. I’ve also written about organic growing and been a member of a growers group for decades.

Organics may not be the only solution

Even so, I’m not an absolutist, and I am a pragmatist . . . I accept that there may be other farming and cultivation systems that could indeed be regarded as “sustainable and healthy” even though they may not pass organic certification. But that’s not my argument here. I’m going to look critically at the notion of why you should buy organic food and whether the advantages stack up — give or take a few generalisations.

Here are the usual reasons for supporting organic food production:

• It’s healthier because few, and low-toxic pesticides are used and residues on crops are not a problem
• It’s healthier because organic food is higher in dietary nutrients
• It’s more sustainable because soil is managed better without chemical fertilizers
• It’s safer and sustainable because beneficial organisms like bees and predatory organisms and wildlife are not poisoned by pesticides
• It’s safer because humans are not poisoned by pesticides as they use them.

Pesticide residues

Even allowing for cheating, it is clear from testing that organic food has fewer residues of detectable pesticides than non-organic food. The issue is whether the presence of residues in non-organic food is a health hazard. Clearly, in some cases it is. The cases of aldicarb pesticide poisoning from melons in California is a classic case. This was only detected because of the severe symptoms. Many other cases are likely in which the victim has less acute symptoms and the cause remains unidentified. And, the effect of long-term exposure to small quantities of residues is unknown, but could be significant.

Testing for safe food. With the world food supply increasingly traded across borders, ensuring “clean” food by monitoring it for contaminants has become increasingly difficult. Recent issues in food safety in relation to food products imported from China make this all too clear.

Organic food has more nutrients

This is the one the professional agriculture, health and nutrition communities have resisted so strongly for so many years. In essence, it is a complex issue. To measure this accurately, you really need to set up controlled growing conditions for a reasonable comparison, and even though quite a few early studies showed advantages for organics in some nutrients like vitamin C, iron, omega-3s and a few other minerals, the design was often somewhat amateurish — until the European Union Newcastle University study came along. Read the results here: “Organic produce better for you”.

Variability abounds. The authors caution that variations in qualities exist across the organic and non-organic spectrum. What this might mean for you, as a purchaser, is that a badly grown organic apple could very well be inferior to a well-grown non-organic apple. One might expect that across a continuum of organic produce, the nutrient value may be higher, but don’t expect that any one purchase will give you that guarantee.

Phytonutrients finally. Over the years of this organic nutrient debate, the one thing that has mostly been absent is an evaluation of the non-vitamin and mineral nutrients. These are the antioxidants, the polyphenolics, carotenes, sulphur compounds, the omega-3s and many more that are known to be health-giving principles in foods. Finally, this also seems to have been answered. In the Newcastle University study:

They found levels of antioxidants in milk from organic cattle were between 50% and 80% higher than normal milk.

This is not surprising, overall, because Alyson Mitchell, associate professor and food chemist at the University of California, Davis, found exactly the same thing in her work analysing tomatoes. Soluble fertilisers, especially nitrogen, and strong pesticides may inhibit the plant production of phenolic compounds. See Mitchell again for a discussion.

One would have to say that early professional bias against the idea of organics having higher overall nutrient values, in a dietary sense, seems to have been ill-founded and perhaps influenced by various vested interests. However, this should not suggest that eating organic foods, even with a premium supply of antioxidants, results in superior health outcomes: that is yet to be proven.

Organic growing is more sustainable

As a general rule this is probably true, and is likely to be more so for smallholdings rather than large commercial enterprises. The definition and evaluation of “sustainability” is variable, but one issue is the recycling of inputs to the system versus importing inputs like organic fertilizers from elsewhere. Sustainability is about being able to make systems last without degrading the system.

Nevertheless, several recent studies — University of Michigan, the USDA and the FAO and others, have found that organics actually outperform conventional agriculture in measures of soil sustainability and biological sustainability — and may even approach the production efficiency of non-organic farms in some cases.

Safer for wildlife and diversity

New Scientist reports: “Organic farming boosts diversity”.

Organic farming increases biodiversity at every level of the food chain – all the way from lowly bacteria to mammals. This is the conclusion of the largest review ever done of studies from around the world comparing organic and conventional agriculture.

Enough said about that one.

Occupational health and safety

This is the sleeper issue in organic production. It receives less attention than other aspects. The human health legacy of toxic pesticides in developing nations has been monumental. And even in the developed nations, the misuse and overuse of pesticides has resulted in substantial impacts on human health. The US Agricultural Health Study has reported on some such results.

Here is what esteemed toxicologists Levine and Doull said about pesticide poisoning worldwide in 1992:

Global estimates of acute pesticide morbidity and mortality. Levine RS, Doull J. Rev Environ Contam Toxicol. 1992;129:29-50.

Mathematical models have projected increasing numbers of pesticide poisoning throughout the world, rising from 500,000 cases/yr in 1972 to 25,000,000 cases/yr in a 1990 estimate.

Summing up

Organic food is more expensive; you have to decide if it’s worth it. In addition, the science of organics is a bit fuzzy at times. Some modern pesticides actually have lower toxicity than approved organic pesticides. The more popular and affordable organic food becomes, the more we will see mainstream food manufacturers taking advantage of it. No folks, the organic pop tart is not a health food. Overall, though, organics is a neat package of environmental health and safety practice. I support it strongly.

New Exercise Guidelines Released in the US

By Paul Rogers

New physical activity guidelines have just been released by the US Department of Health and Human Services. As they report 25.6% of adults in the US are medically obese — that’s a body mass index (BMI) of over 30 — there is an air of slight panic about this latest announcement. Here are the new adult guidelines, which include a few changes from previous guidelines.

1. Adults should do 2 hours and 30 minutes a week of moderate-intensity, or 1 hour and 15 minutes (75 minutes) a week of vigorous-intensity aerobic physical activity, or an equivalent combination of moderate- and vigorous-intensity aerobic physical activity. Aerobic activity should be performed in episodes of at least 10 minutes, preferably spread throughout the week.
2. Additional health benefits are provided by increasing to 5 hours (300 minutes) a week of moderate-intensity aerobic physical activity, or 2 hours and 30 minutes a week of vigorous-intensity physical activity, or an equivalent combination of both.
3. Adults should also do muscle-strengthening activities that involve all major muscle groups performed on 2 or more days per week.

For more information, the physical activity guidelines site has much more information, including useful suggestions for people not used to exercise, and background information for professionals in the fitness sciences.

Physical activity is not all about losing weight — health advantages can accrue in the absence of weight loss – yet unless obese people can be trained or persuaded to cut calorie intake, getting the fat off will continue to be a struggle.

Food for Life, Fit for Life - Lifestyle Training Course Released

By Paul Rogers

Food for Life, Fit for Life - Prevent Diabetes, Heart Disease and Cancer is a set of training modules in lifestyle preventive health.  It took me 12 months to write and it’s now available for licensing. You can download a free ebook version that describes the content. Here’s what’s included:

• Training and evaluation manual for course presenters
• 120 PowerPoint slides with notes and contemporary references
• Sample learner assessment questions for each module
• Fact sheets that can be used as handouts to clients/students
• Risk evaluation self-assessment handouts for nutrition, physical activity, diabetes, cardiovascular disease, and cancer
• Case studies for workgroups and workshops
• Glossary of terms
• Regular newsletter
• US and UK/Australia versions (spelling and units)
• Evidence based information, fully referenced
• Flexible licence conditions and regular, free updates for one year
• Access to a membership web site for support, updates and extra resources.

Background

I started writing this over 12 months ago as a tool to use for talks to clients and groups in fitness and personal training. Rather than the limited training course I had in mind at that time, it has now morphed into something more like a training ‘environment’ with support tools like handout risk assessments and case study tasks. I have plans to add more of these tools and content within the context of the course. For example, a basic ’sports nutrition’ module is near completion.

As a trainer-presenter, your options are varied. You could select various slides or modules for presentations ranging from 2 hours to 2 days to groups or even individual clients. The target audience could include lay people or professionals in various support roles in preventive health. Presenters could include dietitians, nutritionists, fitness trainers, practice nurses, physios, diabetes educators and any support professionals working in preventive and lifestyle health. Some skill in delivering an appropriate language and idiom to audiences with variable knowledge bases would be required by the presenter.

I’ve summarised the essential elements of lifestyle disease, meaning the risks with which we burden ourselves because of our behaviour in relation to food, nutrition and physical activity. Although I mention the roles of environment and genetics, this is not the focus of the program at this time, but I do have plans to add modules that address basic issues in environmental safety in relation to food quality. Any additional modules added are included in the updates available in the licence for one year.

The core elements are:

• Type 2 Diabetes
• Cardiovascular disease
• Cancer
• Obesity
• Motivational and behavioural change
• Nutrition
• Physical activity and exercise

For example, I’ve summarised the complete content of the WCRF/AICR Expert Report: Food, Nutrition, Physical Activity and the Prevention of Cancer: a Global Perspective so that the essential points are clear.

Licences

At present, only one licence option is available. This locks the headers and footers and PowerPoint attributions to me and no changes are permissible. I will probably also offer a ‘professional licence’ under which the licensee has the right to modify the content and replace attribution and headers etc with their identity. This would allow the licensee, with some restrictions, to modify the content and to adjust any particular aspect that did not suit their purpose or premise.

Availability

I’ve created a free ebook (pdf) version of the course, featuring the PowerPoint slide headings with content from the notes of each slide. This delivers a summary version and illustrates the content quite successfully. Not everything is fleshed out of course.

The best way to get this is to fill out the email form on the front page of the web site — or on this blog at the top right. This will redirect to a download page after confirmation. You will then get an email advising when content is updated or added, including new web and blog articles. This would be no more frequent than once each week.

I hope you take a look at the free ebook and let me know what you think. Suggestions, comments and admonitions are, of course, welcome.

Low-Carb Diets Make You Dumber and Slower

By Paul Rogers

Low-carb diets have had their share of weight loss success; and most of it can be attributed to dietary restriction of food choice. That’s how most restrictive diets work, from low-fat to low-carb and vegan: tell people they can’t eat something that’s clearly identifiable, and they will lose weight because choice is curtailed and they find it easier to eat fewer calories.

The trouble starts when they find they can’t maintain such a restrictive regimen — and then they get discouraged, guilty, and the relapse occurs.

But what if low-carb dieting helped you lose weight for the time being, but actually inhibited your personal performance in day-to-day living? Would you continue with it as a lifestyle choice?

What I’m about to discuss does not necessarily apply to moderately low-carb diets, but mostly to ketogenic diets, in which carbohydrate intake is usually less than 20 percent. Even so, there is a possibility that the effects apply across a continuum of low-carb eating from very low to low.

And those adverse effects? Low-carb makes you think slower and move slower.

Low Carb Makes You Dumber

In a study in 2007 in the American Journal of Clinical Nutrition, researchers compared the cognitive abilities of dieters on a low-carb, high-fat (LCHF) diet with another group of dieters on a high-carb, low-fat diet (HCLF) . Here is what they found:

However, the IT test score (a measure of the speed of visual information processing) was affected by diet composition. The results showed that participants consuming the LCHF had significantly less improvement in the minimum stimulus time required to make a correct response than did those consuming the HCLF diet . . . Our findings are consistent with those of an earlier study in obese women showing that performance of a complex, cognitively demanding task assessing mental flexibility was significantly worse after the consumption of a very-low-energy, low-carbohydrate, ketogenic diet than after the consumption of an isocaloric, nonketogenic diet with higher carbohydrate and lower fat content. Similarly, the treatment of young rats with a ketogenic LCHF diet for 1 month resulted in severe cognitive impairment, and a series of rat studies showed that the chronic ingestion of a high-fat diet, in particular a high-saturated-fat diet, can adversely affect cognitive performance.

Low Carb Makes You Slower

In a study in the Journal of the American Dietetic Association in 2007, a team of investigators measured the fatigue and perceived effort of one group of dieters on a ketogenic low-carb diet and another group on a diet with much higher quantities of carbohydrate. Here’s what they concluded:

These pilot data indicate that ketogenic, low-carbohydrate diets enhance fatigability and can reduce the desire to exercise in free-living individuals.

This is not surprising because athletes know that glucose (and phosphocreatine) supply energy at a rate that supports fast, high-powered activities, whereas fat and ketones can only supply energy at a rate biochemically rapid enough for mostly slower activities.

Evidence from the Paleolithic

Now, you might think that would be a good place to leave this discussion — the evidence is reasonably clear — but just for speculative fun, let’s take a look at our evolutionary pre-history and the diets of emerging Homo sapiens — modern humans — in the Paleolithic period of evolution.

About 800,000 years ago, primates moved out of Africa to the north and into Europe to colder climates. This early pre-human form was called Homo erectus, and this species probably evolved into Homo neanderthalis, the Neanderthals, while erectus lived on as a parallel species.

The curious thing is that a second migration of early humans north from Africa started about 50,000 years ago and spread throughout Europe and beyond. It seems that this smart new species, Homo sapiens or ‘intelligent human’, was much more intelligent than earlier species such as erectus and neanderthalis. As far as evolutionary science can establish, Homo sapiens swept all before it and replaced the Neanderthals and erectus with modern humans throughout the world. The other species were out-competed and did not survive.

Paleo Diets and the Evolution of Power and Intelligence

Enthusiasts of Paleo dieting like to contend that early humans were very healthy on a diet mostly of meat, vegetables and some fruit, but virtually no grains or tubers — that is, a low-carbohydrate diet. However, it’s pretty clear that early humans started to eat grains about 20,000 years ago, perhaps earlier, and, according to Richard Wrangham, Elizabeth Pennisi and others, probably ate tubers well before then. See Did Cooked Tubers Spur the Evolution of Big Brains?

Paleontologists have speculated as to why Homo sapiens so dominated the other species in Europe and beyond as they moved into their territory from 50,000 years ago.

Here’s where I speculate that the burgeoning consumption of carbohydrate foods in the form of tubers and grains in East Africa, the cradle of early humans, fed a growing brain that thrives on glucose. Glucose from carbohydrates supplied abundant energy substrate for the evolving brain to build those complex neural networks that we know provides the complex reasoning capabilities of modern humans.

Carbohydrate foods were abundant in the East African savannah. As Wrangham points out: “Today, there are 40,000 kilograms of tubers per square kilometer in Tanzania’s savanna woodlands.” The book The Lost Crops of Africa, documents the prolific grain resources in this region. It would be unlikely if the evolving Homo sapiens did not take advantage of these abundant food resources at some time.

The Neanderthals, by comparison, most likely had a more limited food supply, relying mostly on meat and some vegetables and fruits in season, and eggs but fewer carbohydrate resources, especially in the cold north.

I think it’s a fair bet that Homo sapiens, as they moved north out of Africa from 50,000 years ago, armed with complex brains fueled by rapidly accessible glucose from carbohydrate food resources, simply out-competed the slower moving and thinking Neanderthals and the remaining Homo erectus. Not only were modern humans smarter, they probably moved faster as well.

The thing is, we can still simulate the best qualities of the diets of our ancestors, which were most likely characterised by being low in saturated fat, high in plant foods and fibre, and with sufficient carbohydrate to keep us out of ketosis and to fuel the powerful movement and activity required for good health and fitness.

High carb. Simply smarter, faster.

American Journal of Clinical Nutrition, Vol. 86, No. 3, 580-587, 2007
J Am Diet Assoc. 2007 Oct;107(10):1792-6.

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