You’ve lost weight, but will you keep it off? A low-glycaemic-index diet may work better than others at burning kilojoules and helping people ward off those pesky kilos, according to a study in the Journal of the American Medical Association.
In the study, researchers had 21 people who’d lost 10-15 per cent of their body weight try three different diets, each for four weeks. The diets consisted of low-fat, a low-carbohydrate and a low-glycaemic-index – which endorses carbohydrates that keep blood-sugar levels low – eating programs.
The result: even though the participants ate the same amount of kilojoules on each of the plans, they burned an average of 1260 fewer kilojoules a day on the low-fat diet compared with the low-carb option.
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But the low-carb diet wasn’t a win-win alternative either. Although it was better at encouraging kilojoules burn, it also caused the greatest increases in cortisol and C-reactive protein levels – both of which may elevate heart disease risk – among the study participants.
The low-glycaemic-index diet, however, seemed to strike the right balance in terms of heart health and resting metabolism, says study author Dr Cara Ebbeling.
And any help you can get torching extra kilojoules is beneficial after a big weight loss. That’s because the more weight you lose, the more your metabolism slows, making it increasingly difficult to burn kilojoules, explains Ebbeling.
So is a low-glycaemic-index diet the saviour for people who want to keep the excess baggage from creeping back? The problem of “weight maintenance” may not be so easily solved, warns nutrition expert Alan Aragon. “You can’t tell a whole lot after four weeks,” he says. “And looking at the nutritional makeup of the diets used in the study, you’re really comparing two extremes in the low-carb and low-fat diets to a more moderate diet, which will almost always be best in the long run.”
Avoid diets that condemn whole nutrient categories, he suggests. Instead, eat proven weight-managers – whole foods like fruits, vegetables, whole grains and nuts, as well as proteins like fish and meat. “Your body requires about 10 times more energy to process a gram of protein than a gram of fat. So you’ll burn more kilojoules just by eating more protein-packed foods,” Aragon explains.
Exercise will also play a big role in whether you’re able to fend off the old weight, Aragon says. Running or other aerobic exercise is good, but you should mix in weight training at least half of the time.
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“Resistance exercise boosts lean body mass and metabolism, both of which help your body burn kilojoules even when you’re not working out,” he says. Aim for a minimum of three 30- to 60-minute workout sessions a week, he advises.