Five reasons why doctors shouldn’t ask their patients to lose weight (and five things they should do instead)

Years ago I was the dietetics department manager and proposed that we cease offering weight loss clinics. The dietitians were enraged and others viewed this as anarchic or frivolous but I was deadly serious. I haven’t recommended weight loss to a patient for over a decade and I think to do so is unethical.

  1. Weight loss projects don’t work

Many people are able to lose weight and keep it off for six or twelve months, but the majority regains it by five years.  A meta-analysis found that only 15% of people enrolling in weight loss programmes maintain a 20 pound weight loss at five years. There are good physiological reasons for this.  Doctors shouldn’t prescribe treatments with an 85% failure rate. 

  1. Our body size is genetically pre-determined

Look at your siblings, parents and tell me body size and shape isn’t genetic. And if you’re in doubt, or adopted, look at the studies. The reason some individuals remain slim in our obesogenic environment is because our appetite is hard-wired.

  1. Increasing obesity rates are the result of macro-economic changes

During the post-war depression food was rationed. The British government kept a close eye on nutrition and found you could make the population thinner or fatter by controlling the calories available. The free market has resulted in commodification of food and an oversupply of cheap poor quality food.

  1. We are colluding with industry if we make obesity an issue of personal responsibility

It suits the food, soda, advertising and weight loss industries, as well as libertarian governments to blame individuals for their weight problems. If doctors start recommending motivation and education-based programmes we reinforce the myth that people choose not to be slim.

  1. Asking people to lose weight is unethical.

If doctors prescribe a medicine that doesn’t work, the blame for this is usually levelled at the doctor, or the medicine. But if doctors prescribe weight loss, and it doesn’t happen, it’s the patient who is made to feel like a failure. How does blaming a patient for their illness fit with the Hippocratic Oath?


The things we should do instead are:

  1. Campaign for environmental changes to make living healthier the easy option
  2. Ensure access to bariatric surgery for morbidly obese individuals
  3. Optimize the health of overweight individuals irrespective of weight
  4. Champion compassionate care of overweight people
  5. Fight prejudice on the basis of weight wherever we see it


I wrote The Obesity Epidemic to bust the myth of personal responsibility for obesity. I want overweight people to throw off the guilt and shame and start demanding an environment that supports their living a healthy life. Food seeking behaviours have been selected in our gene pool because they favour survival through times of famine. Only in our obesogenic environment have these become maladaptive. We now need the assistance of governments to restore a physical environment in which the defaults are healthy food and physical activity. Overweight people have the most to gain and I hope this book gives more strength to their arm.


Robyn Toomath, MD, is the clinical director of general medicine at Auckland Hospital, the former president of the New Zealand Society for the Study of Diabetes, and the founder of Fight the Obesity Epidemic. Her book, The Obesity Epidemic: Why Diets and Exercise Don’t Work—and What Does, is available now.