Causes of Overweight

A commentary* by Gary Taubes in New Scientist puzzled me. He has forgotten the simple equation I was taught as a nutrition major:


If E is zero, your weight stays the same; if E is negative, you lose weight and if E is positive you gain weight. It really is that simple, but Mr Taubes says, in his introduction:

FOR the past century, the advice to the overweight and obese has remained remarkably consistent: consume fewer calories than you expend and you will lose weight. This prescription seems eminently reasonable. The only problem is that it doesn’t seem to work. Neither eating less nor moving more reverses the course of obesity in any but the rarest cases.

Mr Taubes argues that causality is the issue – what causes us to want to eat more. This, however, is still saying that we overeat. Even if hormones or a virus or addiction is responsible, if we consume more energy than expended we put on weight. We might not be to blame, but the truth is we are overweight because we took in more energy more than we burnt off.

It is not simple to lose weight. Losing weight requires a lot of effort and, most likely, an change in lifestyle. A change in what is usually quite a comfortable lifestyle. Losing weight is more than deciding not to eat a chocolate bar today. It requires the person to totally change how they approach food and exercise. They need to decide that they are going to change permanently, not just for the next month or so. Old influences will remain and keep on pushing you back to old habits. In fact, losing weight to keep the weight off, is not dissimilar from quitting smoking. The temptation to take up the old habits will always be there.

My story is that I never gained weight. I was one of the lucky ones with a fast metabolism. Then, after becoming a faculty member, I gained weight. I assume it was because I no longer spent long days walking around a lab. Instead I was sitting at the computer all day. I am more accustomed to American portion sizes, than I was in my first few years in the US. I also live in an area where it is more convenient to drive to the grocery (and other) stores – previously I would walk there or pass by on my bicycle on my way home. In other cities, I either had a significant walk (25 mins plus) each way or I cycled for the same length of time. I also was a keen walker (hiker in US terms) and would frequently spend Sunday in the hills around Yorkshire with friends. Somehow, I have not found an equivalent group of friends in my home town. As I have to make time to exercise, I do not do it often enough.

Perception of how much we eat and how we exercise is an issue that is frequently overlooked by writers including Mr Taubes. Thus, he ignores the fact that we perceive what we eat poorly; frequently eating more than we recall. I was glad to see, in the letters, that other NS readers had a similar reaction to Mr Taubes commentary. The first of these web letters states exactly the problem. Dieting does not work, because we do not keep to our diets.

In turns out, unfortunately, his commentary ends up being a plug for low carbohydrate diets. These diets were shown to be just as ineffective as low fat diets once there were enough food products available allowing us to return to our traditional way of eating, roughly three meals a day and snacks between. Initially, when the Atkins diet was first becoming popular, there was very little you could eat while following the diet correctly. Then, there were Atkins diet (or low carb) snack foods, which meant that we could eat in the traditional manner

He does make some interesting points that were made by Yudkin and others before:

… the consumption of refined carbohydrates, starches and sugars, all of which prompt (sooner or later) excessive insulin secretion. Insulin is the primary regulator of fat storage. When insulin levels are elevated, fat accumulates in our body tissue; when they fall, fat is released and we use it for fuel. By stimulating insulin secretion, carbohydrates make us fat; by driving us to accumulate fat, they increase hunger and decrease the energy we expend in metabolism and physical activity.

High sugar foods cause a “sugar rush” and then an opposite downturn in energy. A bit like taking drugs – you get the high, and unless you take more, you get the low. Even though this is a simplified view of the situation, but does imply that the constant consumption of sugary drinks would lead to insulin secretion being over extended.

Remember: If you want to lose weight, consume less calories than you use. You will need to be very honest about it and remove old temptations.


*Sorry, behind a pay wall:
Taubes, Gary 19 January 2008 “Comment: The great diet delusion”, New Scientist Print Edition.