23/08/2012 07:33 BST | Updated 22/10/2012 06:12 BST

Overweight Because You are Eating Too Much? It's highly Unlikely

'It's a weight problem; you can't wait for lunch.'

In a society personified by the ubiquitous golden arches of Mc Donald's and cursive script of Coca-Cola, it's hardly equivocal why the majority of us are now overweight, we eat too much. Simple! We're a population defined by gluttony, with an insatiable appetite for calorie laden foods. The only question on our minds when ordering is; whether to supersize up or forgo the charade and just order two meals. The evidence is everywhere we look, or so we believe. Because the fact is, contrary to what has been engrained in our psyche from every possible advisory authority this assumption does not hold water.

The reality is that the amount of people overeating is far less than the number of people overweight. Indeed, study after study from countries such as the UK, the US, Canada and China all show the same thing: as the rates of obesity have spiralled over a few short decades, our average caloric intake has stayed constant or even decreased. Think of it as two distinct groups, the smaller group consisting of the overweight who eat too much, yet tend to have little inclination to diet, and the larger group who do not overeat, but are still overweight, and are often the ones who resort to dieting.

If we find this hard to swallow, let's take a logical approach. If we are gaining weight from too much food, the obvious solution is to cut back on food i.e. to diet. And, as much as this is touted as the answer to our woes, the stats once again paint a different picture. Of the 250 million Europeans who diet each year, one percent will achieve permanent weight loss [1]. Regardless of the diet type, the scientific studies are unanimous in their findings; that after six to 12 months the weight you lose dieting will start to emerge again, this time with added interest [2]. Our bodies are so resistant to weight loss through cutting calories because it reduces our energy intake below what we need to function optimally i.e. we enter starvation mode. In an act of obstination and retribution a number of mechanisms kick in, not only ensuring that our weight loss efforts are futile, but by shutting down our metabolism it will now be easier to gain weight than ever before [2]. And so it is, we enter the vicious cycle of the diet trap: continually cutting our caloric intake in an attempt to stimulate further weight loss, only to have our bodies stubbornly backlash with further decreases in metabolism. It's the £100 billion global diet's industry claim to fame; not only do they not work, but they make you fatter and as our waistlines balloon, so too do their profits.

Ok, so if energy input has not increased over the last few decades, then what has happened to our energy output? The answer is that it has reduced, dramatically so. Welcome to the technological age, which ensures we don't have to bother with the hassle of expending energy. Active occupations are more or less gone - 10% of men and 20% of women engage in manual labour. We drive everywhere - in 1952 the UK population cycled 23 billion km, this year it will be 4 billion. And, watching television is our national pastime - we average 26 hours a week. Add in the lifts, the escalators, even the automatic doors and you can see there is little time for energy expenditure in today's society [3].

When it comes to actual exercise, we prefer to refrain from that too. With the Euros and the Olympics, it may have been billed the 'summer of sport', but in truth it was the 'summer of sport watching'. We heard recently how nearly two thirds of Brits fail to reach minimum exercise recommendations [4], but astonishingly these abysmal figures flatter a generation of couch potatoes. The figures came from self-reported questionnaires, where people recall how much activity they carry out. And, it seems we are prone to flatter ourselves. In studies where physical activity levels were objectively measured through the use of instruments called accelerometers, the figures shrunk to an appalling 5% or less who were actually reaching minimum recommendations [5].

The statistics are startling and frightening. Add it all up, and we find the difference between the activity levels of living 50 years ago and today is the equivalent of running a marathon a week [3]. Is it any wonder we have a weight problem?

1. Hill, A.J., Does dieting make you fat? Br J Nutr, 2004. 92 Suppl 1: p. S15-8.

2. Rosenbaum, M. and R.L. Leibel, Adaptive thermogenesis in humans. Int J Obes (Lond), 2010. 34 Suppl 1: p. S47-55.


4. Hallal, P.C., et al., Global physical activity levels: surveillance progress, pitfalls, and prospects. Lancet, 2012. 380(9838): p. 247-57.

5. NHS: Statistics on obesity, physical activity and diet: England, 2010.