When clients come in looking smug and saying they've lost two kilograms, my first question is: 'How do you know?', although I already know the answer: they have been on the scales.
This, they kid themselves, will tell them how much fat they have lost or gained. How this could be is a mystery, since the body is made up of water, lean tissue and fat, of which fat is the lightest component. The body's water balance varies normally by up to a couple of kilograms a day. Fat is gained and lost much more slowly. In energy theory terms, it takes at least 8,000 extra calories to make 1kg of fat, but that would depend on whether the excess calories came from protein, carbohydrate or fat, and factors affecting weight gain are more complicated than that.
There is no simple way of calculating body fat as a percentage of total weight. Even the complex body mass index is inaccurate if someone is well-muscled.
So what do these scales addicts, who often weigh themselves many times a day, hope to discover? What they are really asking is: 'Can I be happy or miserable today?' The scales can definitely tell them that. If they weigh less than last time, they believe they have lost fat and feel happy and confident. If the number has gone up, gloom descends.
Both of these responses to weighing are fattening. The first is: 'Oh great, I've lost weight. I can eat what I like today.' This person, who's probably female, lives by food rules. She can feel good about herself only if she weighs a certain magic amount. Today she'll 'allow' herself 'forbidden' foods such as buttery toast, ice cream or chocolate cake. It's OK 'because the scales told me I'm slim enough to relax my rules', she reasons.
The consequence of eating refined sugary, starchy and fatty foods is, of course, insulin surges and yo-yo blood sugar levels which in turn lead to bingeing on more 'sinful' foods. Suddenly she's anxious, not in control any more. Now too scared to face the scales, she keeps eating for a few days until the need to know overwhelms the fear of finding out. She relies on the scales to tell her how to feel. Without that number, she's at sea.
