Almost everyone who has tried to lose weight has tasted the bitter pill of a failure. That feeling you get when, despite all your desires to be healthier, to fit into sassier clothes or to shimmy through life (and into aeroplane seats) with greater ease and comfort, you just can’t stick with your diet and exercise plans for long enough to get there.
People failing to lose weight frequently blame themselves, as does almost everyone around them. In fact, even a sizeable portion of health professionals consider obesity to be an individual failing. But this attitude displays complete ignorance of human physiology and how it impacts weight loss.
Fighting famines, not winning weight wars
In actual fact, most diets fail because the body activates a series of powerful physiological mechanisms – many originating from changes in the hypothalamus, which lies at the base of the brain – that help to protect us from losing too much weight too quickly.
These mechanisms, which I call the famine reaction, have been pivotal to our survival as a species because they prevent ongoing weight loss and promote weight regain. In pre-agricultural times, which forms the majority of human history, food supply was much more dependent on seasons and intermittent. Conserving energy ensured survival through the lean season.
But while the famine reaction undoubtedly helped the species survive recurring famines and hardships, it presents an enormous challenge in modern societies where the abundance of food (especially energy-dense food) means many people are now overweight or obese.