If you’ve inherited a sweet tooth or a tendency to put on weight, you can beat your genes by changing your eating habits and lifestyle. By Helen Hawkes.
Your mother was pear shaped and so are you. She loved fatty foods and sweets and hated exercise – and so do you. Not surprisingly, she was always at least 5kg overweight – and you are too. You may complain about inheriting the shape of curvy model Sophie Dahl rather than Elle ‘The Body’ Macpherson, but it doesn’t have to be that way.
You can outsmart your ‘fat genes’, says Dr Neal Barnard, a clinical researcher in preventative medicine and author of a new book, Turn Off The Fat Genes! (Pan Macmillan). These are the genes and hormones that influence taste, that control appetite and that regulate fat building and kilojoule burning.
“Genetics is not destiny in the case of whether you are fat or thin; rather lifestyle and the environment are,” says Dr Barnard. In other words, while the sweet tooth you inherited from your mother has the potential to lead to weight gain, in most cases this depends on such factors as your refrigerator (your environment) and your exercise regime (your lifestyle).
How to block your fat-storage genes
Many women complain that they seem to have inherited a tendency towards gaining weight, but what they’ve probably inherited is a lack of knowledge about how ‘fat’ and ‘thin’ genes work.
“The fact is, we all have ‘thin’ genes,” says Dr Barnard. “You simply have to put them to work effectively.” He explains that ‘thin’ genes cut off fat storage and turn kilojoules into body heat, while ‘fat’ genes stimulate appetite and push the body to store fat, and that the type of food you eat is crucial to controlling both.
“The most important ‘fat’ gene in the body is on chromosome 8,” he says. “It builds a fat-storing enzyme, called LPL [lipoprotein lipase], which waits inside your blood vessels.
“When you eat fatty foods, traces of fat enter your bloodstream, and LPL then removes them and – if you don’t burn them off with exercise – passes them to the fat layer on your thighs or abdomen. This is how body fat is built.”
To shut this mechanism off, the best thing you can do is avoid high-fat foods. That means choosing low-fat complex carbohydrates and low-fat, preferably vegetarian, proteins, says Dr Barnard. But even lean animal proteins (instead of fatty meats) will push your genes in the right direction.
What does Dr Barnard say about carbohydrates? Should we avoid them all? Simple carbohydrates, like pastries, yes. But not wholegrains or cereals.
“Popular diet books have demonised the hormone, insulin, and the carbohydrates that elicit its secretion into the blood stream,” says Dr Barnard. “Bread is bad. Rice is fattening. Beware of pasta. The image conjured up is that carbs elicit insulin release and it, in turn, drives sugars into the cells where they become fat.”
The truth, says Dr Barnard, is that insulin is your best friend when it is working properly because it is essential to energy production.
“The problem is that some foods, like cakes and pastries, release sugars into the blood too quickly, which causes too much of an insulin response and turns off fat burning.”
Complex carbohydrates, such as wholegrains and cereals, beans, peas and lentils, fruit, green vegetables and pasta, have a slow burn and will help keep insulin levels stable.
And if you can’t imagine life without cakes and pastries? Simple, says Dr Barnard, just re-educate your tastebuds. “Your tastebuds have a memory of only about three weeks, as you know if you have ever changed from whole milk to skim milk.
“At first, skim milk seems tasteless but soon it tastes fine, while whole milk starts to seem too thick.
“If you cut the fat in the foods you eat, it will become second nature within about two to three weeks. Ditto if you cut salt. And if you have not had chocolate for three weeks, you will crave it less than if you had it yesterday.
“You’ll never hate chocolate, but you can definitely reduce the cravings!”
How exercise can help
Exercising your muscles takes sugar out of the bloodstream. It also rehabilitates a sluggish metabolism. But, again, our genes can predispose us to the life of an overweight couch potato.
“If you look at the muscles of people who love exercise under a microscope, they actually look different from those of other people,” says Dr Barnard. “They are rich in special muscle fibres called Type 1 cells which are endowed with a good blood supply – extra capillaries that bring in plenty of oxygen for energy. But, believe it or not, you can change your muscle fibres to make up for what is missing in your chromosomes.”
The exercise Dr Barnard recommends is brisk walking for half an hour a day or one hour three times a week, increasing your time as you feel comfortable. “The muscle-type changes will occur when exercise becomes rigorous and regular.”
Physical activity has other bonuses too. It counteracts the fat-storage effect of LPL, boosts your metabolism so you burn more fat, and helps control your appetite.
Turn Off The Fat Genes! By Dr Neal Barnard is published by Pan Macmillan, rrp $30.
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