Being overweight is often seen to have a simple cause – eating too much and moving too little. It comes as no surprise then that individual weight has now become a “moral” issue in society, where those of us who are carrying a little too much around the middle are blamed for being “greedy”, “lazy” and “lacking willpower”.  While estimates vary, it’s likely that only around 20% of people successfully lose and maintain weight loss, while around 80% of individuals who intentionally lose weight regain it. Clearly 80% of us cannot all be making “bad choices”, so what is going on?

A recent report published by the Endocrine Society helps to shed some light, and summarises what we know so far. And the evidence is in, weight control is much more complicated than we think it is, and the “calories in calories out” mantra simply isn’t good enough.

The central idea to our current understanding of weight is that each of us has a body fat “set-point”, which evolutionary mechanisms drive us to maintain. Think of it as a type of inner thermostat, where you try to maintain the set point at a particular temperature, or weight in this case. The set point can be genetic, but is also largely influenced by your environment, and here’s the rub, it’s much easier to increase your weight set point than reduce it. This theory suggests that even eating very few excess calories over a long period of time can cause our body is reset to a higher weight as its state of “normal”. Some people are driven to compensate for calorie excess by a reduced appetite and a drive to move more, but many people won’t compensate enough.

Weight loss on the other hand will in the vast majority cause our appetites to increase and our metabolic burn of calories to drop, favouring weight regain. One study suggests that our appetite increases enough that we are driven to eat around 100 calories more than usual for every 2 pounds of weight lost. These kinds of effects can continue for years, as reducing the set point either takes a long time or does not happen at all.

Only in recent history has the drive to store fat been a problem, up until now our main problem was lack of food, not too much! Humans have never lived in an environment so set up for weight gain; food is everywhere, all the time.

So what does this mean for our dieting struggles and for our health? Clearly being overweight or obese still brings with it an increased risk of health problems in future, but what can we do if our set point is too high?! The good news is that research into how to reduce weight set-point to a lower level is ongoing, as into the mechanisms behind the drive to gain weight. Until we know more however, its clear that all we can do is try and adopt a healthier lifestyle, very slowly, and avoid yo yo dieting. Rapid weight drops are most likely to be regained, with even more besides, and so our best bet is a weight loss rate of 1-2 lbs a week. Focusing on permanent changes to our lifestyle rather than just numbers is also crucial. Increasing fruit and vegetable consumption, drinking more water, and increasing our fibre intake are all examples of steps we can take to improve our general health as well as helping us with slimming down.

In summary, we can do without the moralising and judgements around weight, and accept that body fat is really easy to gain, and really really difficult to lose. Instead lets focus on what we can do to change our lifestyles for the better, without the heavy scrutiny on the scale. For more information about healthy eating, check out the NHS website.

Charlie Rose Howard, Dietetic Student

Charlie is a BSc Nutrition and Dietetics student at King’s College London. She’s interested in all things public health, child health, and evidence based. Tweet her @charlieroseRD2B


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