How to boost your metabolism

Is your metabolism stopping you from losing weight? Here's how to change it

 

It's an unfair fact that some people burn kilojoules faster than others. But if a slow metabolism is holding you back, you can change it, says Melbourne-based exercise physiologist and motivational coach Mark McKeon. "Genetics are the most important factor in basal metabolic rate [or BMR, the amount of energy we expend while at rest] and there's nothing we can do about that," he says. "But building muscle, staying active and increasing the quality of food you eat all increase your BMR."

Perhaps the number one strategy is increasing your muscle mass. "Muscle burns kilojoules at rest; fat does not. Muscle is eight times more metabolically demanding than fat cells. This is why lean but well-muscled people seem to be able to eat anything without putting on weight," says McKeon. "The BMR of well-muscled people is like a raging inferno," says Sydney-based exercise physiologist and personal trainer Carl Matthews.

He says that, on average, our BMR drops two per cent each decade, but building more muscle will combat creeping weight gain. "But it's important to be assessed and listen to your body," he says. "If you are unwell or stressed, you may need regular eight-hour blocks of sleep or a yoga class to help your BMR work more efficiently." Interestingly, a 2000 study by Yale University researchers found that non-overweight women who are vulnerable to stress are more likely to have excess abdominal fat.

So getting enough relaxation time is probably also important for increasing your BMR.  Of course, regular aerobic exercise and a healthy diet are also important for weight control. While BMR is calculated by attaching electrodes to your body and then finding out how fast electrical current runs through it - muscle is less resistant than fat - you can estimate your rate by using our BMR calculator.

Ways to raise your BMR

• Hit the weights. How much and how often will depend on how active you have previously been, says Carl Matthews. One muscle cell weighs twice as much as one fat cell, but takes up one-fifth of the space. "Therefore your overall weight may stay the same, but your clothes size will come down."
• Reduce stress. It can interfere with the efficiency of your metabolism. Try meditation.
• Raise your body temperature. BMR increases by about seven per cent for a 0.5-degree increase in body temperature. This may be why it's easier to stay slim in summer.
• Exercise in the morning. You will lift your metabolic rate by 10 per cent for four hours.

Eat your way slimmer

• Try eating smaller, regular meals to get the maximum thermal effect (the increase in metabolic rate during digestion) and don't fast. Fasting can reduce metabolic rate by 30 per cent as your body prepares itself for starvation.
• The quality of food is important. Fat is easy to process and has little thermic effect, while protein is hard to process and has a larger thermic effect. Your body works harder to break down the fibre and complex carbohydrates in wholegrains and vegetables than it does to break down refined flours or simple carbs such as sugar. You also need two to two-and-a-half litres of water and vitamins such as B2, B3, B5, B6 and vitamin C.
• According to R. Scott Van Zant of Northern Arizona University, metabolism slows down during the afternoon and evening, which means that food has less of a thermogenic effect when eaten late in the day. If you must eat late, go for lean protein and vegies, he says, and make sure your carbohydrates are complex.

Read our fact sheet on metabolism.