There are weight-losing diets to suit all tastes and persuasions: low carbohydrate, keto diets, Paleo, calorie restricted, clean food, vegan, Mediterranean, Scandinavian, and Chinese, anything you’d like for a sample or lifelong allegiance. Individual after individual will complain of the balance between diet and exercise, how hard they worked, and how difficult it has been to lose weight. That’s not the end. Having lost weight, even a significant extent, is followed in approximately 80 per cent of individuals with a recovery of that weight, usually within 12 to 24 months. In fact, many individuals find their yo-yo weight loss as a seriously unsettling and depressing exercise. And despite the broadest of the recommendation, including repeatedly in this book, that healthy diet and no obesity have major impacts on your health span and life expectancy, the troubling scenario continues: weight loss and disappointment.
A January 2020 article in Nature, one of the world’s most prestigious scientific journals, was headed ‘Unexpected Clues Emerge About Why Diets Fail’ and became one of the most eagerly read articles of 2019 when excerpted earlier in the New York Times. A central example used to set up the discussion was the American TV show on weight loss titled The Biggest Loser. At the end of the designated TV time all the contestants had lost 50 pounds (22.7 kg) or more. The diets were intensive and involved significant exercise. Watchers could take the message to heart. But a few years later, within two years for some, on average two thirds of the weight lost had been regained. Some dieters ended up heavier than when they had begun the programme.
Reviewing the extensive literature suggested that various attempts – behavioural, psychological and dietary – to arrest the weight recovery usually failed. One observation seemed to provide a pertinent explanation is that the Biggest Loser contestants later slowed their basic metabolic rate, a measure of their caloric need for their bodies, by as much as 400 calories per day, and this reset was seen up to six years later.
If you begin with the premise that you will embark on a diet that reduces your intake by 400 calories, associated with a satisfying weight decline, then the body trashes your reward by adapting to a new low intake, and weight comes back. Most successful weight-losing studies might run for six or 12 months, but clearly a longer period is needed to ensure that the outcome is more permanent. For the great majority this is just not so.
Multiple other research approaches to the problem of obesity and weight regain have been pursued, including hormonal, genetic, behavioural and environmental. It seems almost certain that there will be no single magic-bullet explanation and practice for the majority of people to lose weight easily and keep it off.
As there is no doubt that significant obesity is associated with a range of unsavoury health problems, the ongoing efforts for individuals to struggle to keep their weight down seems a difficult but nonetheless sensible objective. Most health problems are a combination of genetic susceptibility, commonly contributing only modestly to a disease risk, to the pattern of food intake, to environmental and behavioural interactions, and exercise. While one size doesn’t fit all, for most individuals experiencing obesity multiple interactions are required to achieve ends.
From Ageing Well: How to Navigate Life’s Journey in Your Later Years by Dr Doug Wilson, published with permission of Calico Publishing.