Have you noticed that those who feel it necessary to go on a diet lead a kind of yo-yo existence? A lot of will-power and effort is used up in adhering to the strictures of their diet of choice and some weight is shed, at a faster rate at the start of the diet and then weight loss slows down. However, as soon as they take their foot off the metaphorical pedal the weight piles back on again to such an extent that in no time they are back where they started again. And so the vicious cycle starts again – diet, weight loss, stop diet, weight gain, diet etc. The only winners in the whole process are those who peddle the diets and dietary products, a multi-billion dollar industry world-wide.
Two questions occur to me – why bother dieting and does dieting lead to long-term weight loss? A paper I came across published in the ever popular and slim-line Neuroscience and Biobehavioral Reviews attempts to shed some light on these issues. For a scientific lay-person like me the gist of the argument is that there is a narrow band of weight where dieting might work. Otherwise you may just as well give up and resign yourself to being a lard bucket.
The facts are quite startling. A study of 176,000 obese people conducted over a period of 9 years showed that an astonishing 98.3% of men and 97.8% of women failed to get to what was perceived to be a healthy weight level again. And there seems to be a biological reason for this startling failure rate. Once you become obese, fat cells proliferate and dopamine signalling in the brain encourages you to increase your level of consumption. If you try to do something about your weight by dieting, the body senses that it is being starved of sustenance and tries to force you back to your former, large size.
The rub is that the more weight you lose, the stronger is the biological pressure to revert to your previous shape. Even if you return to what is perceived to be a normal weight they need to consume around 300 fewer calories a day than those who have never been obese. More worrying still, the researchers have found that the biological adaptations that have a predilection to return you to your former shape persist indefinitely. The best you can hope for is a temporary remission.
There is better news for those who are overweight rather than obese, those whose Body Mass Index is in the fairly narrow band between 25 and 30. For these a change of diet and adopting an exercise regime is likely to work because the biological adaptations that are at work with the obese do not seem to be a factor.
The natural conclusion from all this is that absent some form of drastic surgery like the fitting of a gastric band, the obese are pretty much stuck where they are. The consequences of that for future healthcare costs are enormous (pun intended). It also suggests that the global diet industry is at best built on shaky foundations and at worst a confidence trick feeding on the gullible. It also means that government strictures, echoed by some parts of the medical professions, shaming the obese into some form of action are doomed to failure and will only lead to further misery and despair.
Far better, it would seem, is to extend the nanny-statism that seems to be OK for drugs, alcohol and tobacco to sugar, fizzy drinks and foodstuffs with minimal nutritional value. Now that would really be something.