Why Are We Fat?

• policy
• food

It turns out there are possibly scientific excuses — sorry, reasons — why I, along with most of the Western world, according to well-meaning TV chefs and hysterical headlines, am plump. The blame for this is usually laid at the feet of unhealthy food and increasingly sedentary hobbies (such as browsing websites, you porky reader you).

A number of the excessively sanctimonious seem to blame the growing tidal wave of blubber on fast food, which is apparently only consumed by people lacking in education (and, one assumes, impulse control). Of course, nobody with a high-class education (which presumably includes simple biology) would ever eat pie 'n chips. They'd eat foie gras.

We are exposed to health lectures in school 'personal education' classes as well as biology lessons, cheeky cooking chappies crusading on the gogglebox, not to mention every women's magazine in the world exhorting us to try miracle diets and critically examine other people's lipidous zones. Even without the awesome power of simple observation, you'd have to work really hard to stay ignorant of the fact that fatty and sugary foods make you fat. Do you really think all of us overweight people are stupid as well?

The problem is this: eating is really enjoyable and satisfying. Evolutionarily speaking, we are the product of people who gorged themselves silly when they had the chance, so they had convenient energy reserves for chasing buffalo or surviving Ice Ages and the like. Liking food, indeed being a bit greedy, helps you survive. Pretty good payoff. Unsurprisingly, your brain knows this too, and eating fires off endorphins that make you feel good and keep doing it. When you add in the fact that smell and taste retain a strong connection to the hindbrain, allowing them a fast track to your emotions, restraining your urge to eat seems a lot harder.

How much are we allowed to eat, anyway? You're told you'd be healthier long term if you were 'the correct weight': leaving aside the incredible human ability to ignore long-term risks — hello smokers! — what is the right weight? The standard government assessment is the Body Mass Index, or BMI, which is your weight divided by your height squared. As the unit of kg/m^2 indicates, it is a ridiculous measurement. It does not allow for:

• differences in build
• the fact that muscle weighs more than fat
• the fact that the boundaries between under-, normal- and over-weight are disputed and subject to change
• measuring people's body fat percentage relative to their BMI reveals that you can have a 'normal' BMI while having anything between 10 to 50% body fat. Is that really a helpful measurement?

Of course there are better ways to determine if it might be an idea to lose weight, ranging in technological advance from studying your x-ray absorption signature to the humble tape measure. And much as I hate to admit it, I probably should lose some weight. Why is it so damn hard?

Psychological researchers at Florida State University may have found a contributing factor. In their experiment, subjects were required to screen out distractions that flashed up while watching a video. After concentrating on this task, participants had a lower level of glucose in their blood. This was true for other tasks requiring self-control, like not eating cookies (or not being racist, apparently). But, in a double whammy, participants with lower glucose performed worse in subsequent tasks requiring attention focus and self-control. Providing them with more blood sugars improved their tenacity and willpower again.

Unfortunately for me and my plump comrades, this study seems to demonstrate that resisting your basic urges — like the drive to devour cookies — is harder when you're low on glucose — which you get from cookies. And the act of resisting cookies lowers your glucose levels further, presumably until you give in. Whereupon, because you've just had another dose of blood sugar, you will be all fired up on will-power again. Just in time to berate yourself for your cookie obsession. In other words, dieting makes it harder to diet. This seems to be rather unfair, and I will be petitioning any Intelligent (or otherwise) Designers I find on this matter.