SCMP Monday, July 9, 2001

Keeping Fit - The caveman diet
LAURA WALSH
According to the statistics, 95 per cent of people who try to lose weight will gain it all back - and more - within five years. So why is the failure rate so high? And, with the World Health Organisation now considering obesity an epidemic, why are people all over the globe getting fatter?
To begin to understand what is happening, we must go back to our prehistoric days when we had to hunt and forage for our food. There was no ParknShop. While we have evolved intellectually, our bodies are still stuck in the cave.
Food back then was basic, without additives or, more importantly, processed sugar. So not only were we using up much more energy in just acquiring our food (not just opening up the menu and placing an order), the food had fewer calories. And calories must be used up as energy or it is stored as fat.
But what about your best friend who can eat anything she wants, never doing any of those exercise classes you drag yourself to, yet never gains weight? It all comes down to hormones and genetics. Unfair, yes. But just remember she would not have been a survivor in prehistoric times.
So is losing weight, just a matter of using up more calories than you put in? Basically, yes - but there's a bit more to it than that.
First, while exercise is crucial, it is only part of the equation. Exercise needs to go hand in hand with healthy eating: you are what you eat!
Researchers originally thought fat was the enemy and that by eliminating or reducing products with fat we would all become slim and trim. Now, they are discovering sugar is the culprit.
This has to do with a hormone called insulin that is produced by the pancreas. When we ingest sugar, our blood sugar increases and tells our bodies to release insulin, which then binds to cell receptors acting like a key opening a lock. Once open, the blood sugar can enter and energise all your cells. Whatever is not used up for energy is stored as fat.
Sugar is not just the white granular stuff - it's all the bread, pasta, fruit, flour, corn syrup, vegetables (yes, veggies are mainly made up of sugars) and all carbohydrates. When you overeat carbohydrates for too long, your body develops a condition called hyperinsulinemia, or insulin-resistance. The number of receptors that insulin can open diminishes and so more calories are stored as fat than used up as energy. This, in turn, causes the calories that do end up getting through to your cells to be used much more efficiently. And of course, you gain weight.
Another theory used to explain weight gain is insufficient sleep. When you don't get enough sleep, at least 10 different hormones are affected and, again, this comes down to our prehistoric condition.
A new book, Lights Out, by Dr Bent Formby and T S Wilet, proposes that during the winter months we hibernated, with little activity and food, in order to survive the famine. In summer we feasted in anticipation of the famine and played in the long hours of sunlight. But with the invention of the light bulb we have managed to fool our bodies into thinking it is summer continually. So our bodies are always anticipating the scarce food supply and inactivity to come. As a result, we are always storing fat and slowing our metabolism in order to sustain us through the winter months of hunger that never arrive.
So what do all these theories mean to you and your efforts to lose weight?
Basically, we are still biologically living in a cave. So maybe we should try to think like a caveman when it comes to weight loss: go fetch your sandwich at lunch time instead of having it delivered.
A little more sleep may take your body out of its hoarding mode and curb those cravings for carbohydrates and processed sugar that never existed during our ancestors' time.
Email Laura Walsh at alihk@netvigator.com .