Sedentary behaviour did not cause this obesity epidemic
… and exercise will not cure it
The UK government (Department of Health 2004) document, “At least five a week”, notes that exercise is only claimed to have a medium level of evidence for moderate preventative and therapeutic benefits for obesity i.e. the evidence is not strong for there being much benefit either as a prevention or a cure. (Ref 19)
The USA government admits that data to support the idea that more active people are less likely to gain weight “are not particularly compelling”. The one study that was done, to see if the weight gained by the average American over the past thirty years was due to food intake or activity concluded that food intake was to blame. (Ref 20)
The Deakin study actually found that activity levels had risen, during the period of the explosion in obesity, and that obesity levels would have been even higher were it not for this.
The official evidence simply does not present a case for sedentary behaviour being the cause of the obesity epidemic. The rise in obesity started at the turn of the 1980’s (yes – exactly when we changed our diet advice). Nothing happened to activity levels at that time, or around that time, that could even start to explain the subsequent tenfold increase in obesity (from 2.7% in 1972 in the UK to 25.8% at the turn of the new millennium). (Ref 21)
It is a simple and unavoidable fact that we can eat in one minute enough fuel for one hour. The relative importance of not putting something in our bodies in the first place massively outweighs the idea that we can eat what we want and burn it off with exercise.
There is also the fact that exercise is best fuelled by eating carbohydrate and weight loss is best achieved by carefully managing how much and how often you eat carbohydrate. Working exclusively in the field of weight loss, the most difficult clients for me to help are vegetarians (who don’t eat the only zero carb foods available – meat and fish – although eggs are virtually carb free) and fitness enthusiasts. The latter require a steady supply of carbohydrate and this keeps their body in fat storing mode rather than fat burning mode.
For another bit of common sense – it has been as necessary for our evolution that we conserved energy as it has been that we gathered energy. We would not be here today if we burned off what we ate. The idea that man is naturally active is a myth. Cave man would find the activities that we have invented today (aerobics, spinning, marathon running) quite funny. Man is as evolutionary disposed to being sedentary as he is to gathering food. What man would have done, and what we should do today, is natural activity. Walk, talk, sing, dance, cook, clean and tend the land – that’s what we should do. Not pumping iron!
Ref 19: Department of Health, At least five a week, (April 2004). (See reference 311 The Obesity Epidemic)
Ref 20: Swinburn B., “Increased energy intake alone virtually explains all the increase in body weight in the United States from the 1970s to the 2000s”, 2009 European Congress on Obesity, (May 6-9, 2009). Abstract T1:RS3.3. (See reference 285 The Obesity Epidemic)
Ref 21: https://apps.who.int/infobase/Indicators.aspx. Wadsworth M, Kuh D, Richards M, Hardy R, The 1946 National birth cohort (MRC national Survey of Health and development). (See reference 3 The Obesity Epidemic)