You will notice that headline said: “Why Can’t Fat People Lose Weight?” rather than: “Why Fat People Can’t Lose Weight”. The second headline implies that it’s all over and if you’re fat you have no hope of slimming down — permanently. But that’s not the question because fat people definitely can lose weight. It happens all the time when people get sick and die. It’s called the First Law of Thermodynamics. And no, this is not some abstruse and irrelevant pun, it’s at the very core of how weight control needs to be approached.

What we don’t need is a new distraction based around a new nonsense like ‘leptin resistance’ (and see below) that gives people an excuse not to control their energy intake and expenditure. Insulin was once the big bad hormone, and now leptin is showing signs of being the new insulin.

With the obesity epidemic in full swing, and the incidence of obesity and diabetes (and other associated diseases) set to mushroom in the next decades, it seems professionals are rushing to provide explanations for why this obesity pandemic is out of control in developed countries and soon to follow in emerging super states like China and India as affluence blooms. Obesity in the 2000s  is very much a product of the inevitable relaxation of environmental and social constraints that come with affluence — and by affluence I mean cheap food, abundant availability and less physical activity — in work, leisure, travel or transport.

The New Hormones

There are no new human hormones of course, only new ones to focus on. Insulin was a focus in the most recent decade, when diet books and fitness protocols tried to tell us it was all about insulin and if you controlled it you would not get fat and could look like Mr Universe. This was always a half-truth. Now it’s a new tray of hormones — the ones that pop up or down when the body senses it needs to feed or stop feeding — the appetite and satiety hormones.

Exercise and diet (calorie restriction) are the mainstream recommendations by weight loss professionals when advising clients how to lose weight. Organizations such as the The National Weight Control Registry and WeightWatchers record the fact that this can be a successful approach to fat loss and ongoing weight management for many people.

However, for people who are not successful, an inability to control excessive eating may be a cause of this lack of success. While this may simply be lack of determination and will, or even inadequate information, pundits such as Gary Taubes claim that exercise does not work for weight loss because it stimulates appetite excessively. Others say that certain types of exercise make us hungrier — or even suppress appetite better than other types. What do we really know about exercise and appetite?

The Satiety and Appetite Responses

The human body has a sophisticated system of hormones that affect basic human physiological function. Hormones are essential chemical messengers that cells in the body send out to influence other cells and achieve a particular bodily function. Some of these hormones reflect and react to feeding or fasting. The appetite and satiety hormones, to a certain extent, tell us when to eat (appetite) or when we feel full (satiated). Here are four important satiety and appetite hormones.

  • Insulin is produced by the pancreas in response to food intake, especially protein and carbohydrate. At the same time, insulin dampens appetite by sending signals to the brain. In overweight and diabetic people, insulin resistance may cause this regulation to malfunction.
  • Leptin is produced by fat cells, increases with body fat levels and is higher in fat and obese people. Leptin is also supposed to dampen appetite in a manner similar to insulin – sending brain signals. However, leptin resistance may also be a factor in wayward appetite in overweight people.
  • Ghrelin is released by the empty stomach and its role is to stimulate appetite. Once food is consumed, ghrelin release abates in people with normal metabolism.
  • Peptide YY (PYY) is another gut satiety hormone, this time released from the intestines. Its role is to dampen hunger as food is consumed.

Various other appetite hormones have been identified and others are being explored.

Exercise and Appetite

In the weight loss, fitness and bodybuilding industries, promoters of services are looking for an angle: a new supplement, a special exercise or piece of equipment, a radical diet, or even a system of exercising that is supposed to help you lose fat and build muscle in a new way.

One of the approaches is to suggest that a particular type of “metabolic” exercise program will burn off that fat and build muscle while keeping your appetite under control by manipulating one or more of the hormones mentioned above. These training programs tend to disparage cardio and promote high-intensity weight training, circuits and interval training. So what’s the truth about such programs?

Various types, volumes and intensities of exercise have been investigated as to their overall effect on appetite and satiety over the short and longer terms. No consistent result has emerged regarding type of exercise, yet the overall evidence suggests that:

  • “A better short-term appetite control has been described in active compared to sedentary men, and an exercise intervention was shown to improve appetite control in previously sedentary individuals.” (Martins).
  • Also: “Evidence suggests that chronic exercise training typically causes a partial but incomplete compensation in energy intake perhaps due to beneficial changes in appetite-regulating hormones.” (Stensel).
  • And: “These findings suggest that large energy deficits induced by exercise do not lead to acute compensatory responses in appetite . . .” (King).

One point to note is that there are significant differences in how exercise affects appetite and satiety in individuals, and perhaps even gender. Anecdotally, swimming has been suggested to increase appetite greater than other activities. Scant evidence exists for this idea and there is minimal knowledge about specific exercise modalities and appetite and satiety.

Ultimately, exercise is an important part of any weight loss program and does not, by itself, cause compensation and overeating in most regular exercisers. Even so, trainers, dietitians and other weight loss professionals should take care to advise clients not to regard exercise as a licence to binge eat. Rather than a physiological response, this type of overeating seems more a psychological response, and one that can probably be curtailed when the relevant energy quotients of various foods and exercise sessions are explained clearly. In addition, what seems to be useful is a wide-ranging program that includes weights, cardio, and some high-intensity interval work as fitness allows.


- J Nutr Metab. 2011;2011:237932. A review of weight control strategies and their effects on the regulation of hormonal balance. Schwarz NA, Rigby BR, La Bounty P, Shelmadine B, Bowden RG.
- Appetite. 2010 Jun;54(3):492-8. Influence of prolonged treadmill running on appetite, energy intake and circulating concentrations of acylated ghrelin. King JA, Miyashita M, Wasse LK, Stensel
- Ann Nutr Metab. 2010;57 Suppl 2:36-42. Exercise, appetite and appetite-regulating hormones: implications for food intake and weight control. Stensel D.
- Int J Obes (Lond). 2008 Sep;32(9):1337-47. A review of the effects of exercise on appetite regulation: an obesity perspective. Martins C, Morgan L, Truby H.




Sitting Bull: How Sitting Affects Cardiovascular Risk

by Paul Rogers on October 19, 2011

Now Sitting Bull was the famous Native American chief who defeated General Custer at the Battle of Little Bighorn. But that’s not what I’m going to talk about here. Take this quote for example from ABC Australia and Professor Marc Hamilton, a researcher into the dangers of “sitting”.

“The studies show sitting for long periods can be dangerous to health, even when people exercise regularly, increasing the risk of heart disease and other conditions by 80 per cent.”

And . . .

“Even people who are lean are at risk for this, so we’re not immunised by being lean and exercising and eating a healthy diet.”

One would think that sitting is an absolute risk factor for heart disease and related conditions like diabetes, but is this so?

There is no doubt that in population studies (Healy et al), sitting for long periods is associated with an increase in cardio-metabolic risk  factors like inflammation, waist circumference, triglycerides and insulin resistance. I understand that public health authorities and advisers and researchers in the scientific community need to get a simple message across — which is that we need to move more for metabolic health and fitness, and that sitting, especially for long uninterrupted periods, may work against this.  What I don’t buy is that sitting is a primary risk factor and that even if you exercise and stay lean, your risk of heart disease and associated conditions is increased with prolonged sitting — independent of the formal and proven metabolic risk factors, which is what the spiel on this subject, above, implies.

Here’s a theoretical case study. An amateur triathlete and ‘weekend warrior’ likes to compete in weekend triathlons . . . nothing too serious but he has to be fit to get around the 1500 metre swim, 40 k bike and 10 k run. He’s 40 and works as an IT consultant, often sitting for 6 to 8 hours/day. He trains for about an hour a day, six days a week, sometimes a little more, mixing swimming, cycling and running. He’s very fit, but he’s not exactly an elite athlete, and  he mirrors what many men and women do in their recreational hours to keep fit and healthy. His diet is pretty good as well.

On the metabolic and cardiorespiratory front he has a total cholesterol of 4.5 mmol/L  (175 mg/dL), fasting triglycerides of 1.0 mmol/L (88 mg/dL), fasting glucose of 5 mmol/L (90 mg/dL). His body fat is 10 percent. His resting heart rate is 50, his heart rate reserve is 140. His VO2 max is 62. This guy is at increased risk of heart disease because he sits at his job all day? I don’t think so.

My triathlete is theoretical, but I know the numbers are close because I’ve been there, done that, and trained with amateur triathletes, fun runners and marathoners. Even so, others will do much worse (and some will do even better) for these metabolic parameters, even with strong exercise regimens. Yet the proof is surely in the pudding: sitting is not a primary risk; the metabolic numbers are what counts. Get them right and you can sit until the cows come home. The message regarding being sedentary, of which sitting is part, needs to be put more qualitatively and . . . well . . . quantitatively regarding physical activity. Or else show me the proof.

Healy GN, Matthews CE, Dunstan DW, Winkler EA, Owen N.Sedentary time and cardio-metabolic biomarkers in US adults: NHANES 2003-06. Eur Heart J. 2011 Mar;32(5):590-7.


Weights or Aerobics for Fat Burning? It’s All About Energy Expenditure

September 5, 2011

I’m always amazed at how easily nonsense gets a hold in the fitness community and spreads like wildfire. One concept that has received widespread dissemination over a decade or longer is that weight training is better for fat loss than aerobic training. Various ideas about this have been propagated, including more muscle means more resting energy expenditure, […]

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What You Need to Know About Healthy Bones

March 21, 2011

Worrying about their bones is not something that teenage girls give high priority to – not in relation to how strong they are going to be in 20 years anyway. Nevertheless, building strong bones in adolescent and teenage years is crucial to having strong bones throughout life and into old age. Some older men and […]

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How Physical Activity Prevents Lifestyle Disease

December 20, 2010

Compared to how humans lived prior to civilization, and even how people lived up until the present century – and some still do – we in the developed nations move very much less. It may be obvious, it may be overstated and it may seem trivial in the scheme of healthy living, but it is […]

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All About Energy Systems for Physical Activity

November 8, 2010

Introduction to energy systems When we exercise, depending on intensity and duration, fed state and other variables, a mix of energy systems is used, but often one dominates, depending on the nature of the activity. Food is fuel, and understanding the principles of refueling and types of fuels required for particular activities is important in […]

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Best Diet Before and After Prostate Cancer

September 27, 2010

Much more has been written about dietary prevention of prostate cancer than about what to do after a diagnosis of prostate cancer. The approaches could very well be similar. However, in this small summary, I’ll look mainly at dietary approaches post prostate cancer diagnosis. Dietary Prevention Somewhat oddly in my view, most of the dietary […]

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The Basics of Longevity, Anti-Ageing and Life Extension

August 20, 2010

Theories of anti-aging and life extension abound. Genes no doubt have a major role to play, and aging seems to be a programmed genetic decline that is inevitable. Yet the fundamental theory that interests us here is the idea of accumulative environmental damage to DNA, chromosomes, cells and cell reproduction over time, mostly caused by […]

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High Meat Diets Linked to Inflammatory Bowel Disease

July 12, 2010

In this study from France, 67,581 middle-aged women (40-65) were followed for 10 years, while their diet and disease status in relation to inflammatory bowel disease (IBD) were recorded regularly. (IBD includes Crohn’s disease and ulcerative colitis in which intestines and the colon become inflamed.) This is what they found. High total protein intake, specifically animal protein, was associated […]

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Maintaining the Ageing Brain for Wellness

June 24, 2010

The brain wears out; it’s as simple (or as complex) as that. The ageing brain has a propensity to lose function, but you can do a lot to slow or halt this progress. Various dementias and Alzheimer’s disease are possible outcomes. Both result in substantial and progressive loss of mental capacity — and in the case […]

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Why You Can’t Substitute Fat and Protein for Carbohydrate in Athletic Endeavour

May 31, 2010

Low-carb dieting still has many followers after many years. Some people find it works for weight loss — if they can stick to it for any length of time. Yet the proponents and supporters of low-carbohydrate dieting are always looking for one more angle to boost the somewhat low credibility of low-carb eating among most […]

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New Thesis Theme for FoodFitHealth

May 4, 2010

I just swapped the WordPress theme over to Thesis 1.7. All my blogs will be using this now. It has a great deal of flexibility and relative ease of use and I don’t know a WordPress theme to match it. Still some tweaking to do, but it slotted in without much hassle at all.

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Trekking in a Wild World – Patagonia

April 27, 2010

I just got back from an amazing trekking holiday in Patagonia in Chile and Argentina — two months in some wild and beautiful country across the Andes, lakes and volcanoes. The pic below is from a tough hut-to-hut walk outside Bariloche in Argentina. My partner and I are not new to this sort of activity, having trekked […]

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The Truth About Saturated Fat

January 26, 2010

Traditional dietary advice for prevention of heart disease says we should keep our intake of saturated fat low and eat more unsaturated fats like vegetable seed and nut oils and olive oil, which have some saturated fat but are much higher in the polyunsaturated and monounsaturated fats. Although some vegetable oils like coconut and palm oils are high […]

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Are the Framingham Heart Risk Tests Useless?

January 4, 2010

I trust everyone who had a holiday break over December is refreshed and ready for another long, hot and sweaty year — either from climate change or your exceedingly vigorous exercise regimen. The Framingham Heart Study and Risk Factors Commencing in 1948, the Framingham Heart Study is the largest and longest running study of cardiovascular […]

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So Long and Thanks for All the Fish – Is Paleo Dieting Finished?

December 22, 2009

The Paleo diet and its many forms has made quite a splash over the last decade on various internet web sites and forums, all supported by books like Neanderthin and The Paleo Diet. But new archaeological research findings have questioned the central theme of the Paleo diet — our genetic incompatibility with grain and carbohydrate foods. If you’re not familiar […]

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Is Your Heart Bullet-Proof?

October 13, 2009

I credit Rad over at Eons for alerting me to the specifics of this heart rate recovery test, although I was aware that heart rate recovery research in relation to cardiovascular health had been around for some time, using various medical and fitness treadmill stress tests like the Bruce or Balke protocols. According to the researchers working in this […]

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How to Improve Restrictive Diets with A Few Tweaks – Atkins, Ornish, Vegan

October 2, 2009

I’m not a big fan of low-carbohydrate diets, or most other restrictive diets for that matter. For one thing I’ve been doing hard exercise since I was 10 years old and I’m not about to stop anytime soon. You need optimal quantities of carbohydrates and a reasonable quantity of quality fats and protein for health […]

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What You Need to Know About Burning Fat

September 17, 2009

  The idea of “fat burning” has become something of a cliché these days. I’m not surprised. It sounds logical that if you want to lose weight you should burn up that body fat that makes you fat . . . right? In a way that’s correct, but what has been grossly misunderstood — even […]

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Don’t Go Belly Up – Control That Waistline

September 7, 2009

A big belly is potentially a health warning — for men and women. True, there may be metabolic types that defy the general health implications of a substantial girth. Some men and women might actually be metabolically normal with a large waistline — especially if they are physically active — but I wouldn’t count on it. […]

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