Put a fire in your belly

You want to shed some kilos, and you've spent a small fortune on gym memberships and diet products. But you're still stuck with belly fat and your fitness levels aren't improving.

If this sounds familiar, you're too preoccupied with zapping calories during a workout when you should be thinking about how to boost the afterburn. Bumping up your basal metabolic rate (BMR) can help the body scorch fat all day - even when relaxing in front of the television.

BMR is essentially the 'minimum rate at which your body uses energy at rest,' says Carmen Lo, a registered dietitian. It's the bare amount of calories needed to keep you alive. It enables processes such as blood circulation, lung function, tissue repair and so on. Although it's largely genetic, there are some components that can be altered.

First, it's directly proportional to lean body mass, says Kendy Tam, a registered dietitian and a Hong Kong Nutrition Association committee member. The more muscle you have, the higher your body's fat-burning ability. We lose muscle mass at a rate of about 0.5 per cent a year past the age of 25, so it pays to build and maintain that storehouse.

The second component of metabolism - albeit a small percentage of it - is the thermic effect of food. When you eat, you not only consume calories, but also burn them, says Lo. This is because the body uses energy to digest, absorb and store the nutrients in food.

The third, most easily influenced and largest element of metabolism, is physical activity. The more you do, the more calories you burn - even in hours following exercise. This year, researchers from the University of North Carolina and Appalachian State published results from their first study using a metabolic chamber - a US$1 million 2.4-metre by 3.3-metre space that volunteers stay in overnight. It found 10 men who exercised vigorously for 45 minutes in the morning continued to burn calories over the next 14 hours. It was proof that 'afterburn' exists. Sadly, most of us don't get enough activity and work in sedentary jobs.

While it's unlikely you can change your job (or your genes), simple tweaks to the way you eat and exercise can stoke your body's natural fat-burning furnace.

Eat frequently

This isn't a licence to pig out. Dr John Berardi, author of The Metabolism Advantage, recommends eating small meals at two to three hour intervals to boost your metabolic rate. This means splitting larger meals into smaller meals. In effect, you eat five to six meals a day. In addition, eating small meals serves to regulate your appetite, so you'll be less likely to overeat. It may even help decrease LDL (that is, bad) cholesterol and stabilise blood sugar levels in healthy individuals, says Tam.

Eat protein

Include some form of protein - eggs, nuts, lean meat or cheese, for instance - in all your meals. 'Fat requires the least energy to be broken down before it can be used by the body, whereas protein requires the most,' says Lo. That's because protein contains nitrogen, which must be removed before the body can use it. This extra step requires more energy. In addition, protein builds fat-burning muscle, so it's win-win.

Do short, intense workouts

For weight loss, that 10 kilometre run may actually be less effective than a few sets of 100 metre sprints, according to Ed Haynes, head of fitness and performance at New Territories-based Coastal Fitness. 'Steady-state training tends to burn more calories during the session, but interval training burns almost twice the amount of calories after the workout,' he says. While you shouldn't rule out endurance sessions, interval training is time-efficient and adds variety, says Haynes.

Justin Lee, a strength and conditioning specialist and fitness coach from Kitchee Sports Club in Tseung Kwan O, notes that an anaerobic workout releases more human growth hormone - a response to the micro-tears in muscle tissue after intense exercise - that burns fat and builds muscle. High-intensity exercise also increases the body's post-exercise oxygen consumption (EPOC, or afterburn) boosting metabolism and fat burn even after the workout.

Try this workout recommended by Haynes. Head to a running track, sprint for 50 metres then walk for 10 metres. That's one set. Aim for anything between five to 20 sets, depending on your goals and ability. Alternatively, you can try a pool workout by doing a freestyle sprint for one lap and immediately going for a recovery lap with the breaststroke. Rest 20 seconds before going for your next set. 'Use your creativity to design and plan your own interval workout,' he says.

Tweak your gym session

The hard-and-fast principle of interval training applies to the gym as well. Forget about isolation exercises like bicep curls, tricep kickbacks and leg extensions. Instead, focus on compound exercises like the bench press, deadlift, squat, pull-up or push-up, says Haynes. 'If fat loss is your goal, you should do exercises that recruit more muscles,' he says.

Keep your sets per exercise in the range of three to four, Lee recommends, as that is sufficient for muscle gain. A Greek study found that doing more sets didn't provide a substantial increase in fat loss. Aim for around eight to 12 repetitions with a weight that is heavy enough to make it difficult for you to complete your last rep, says Lee. Limit your rest periods to about two to three minutes. This is the optimal level for the balance between recovery and intensity.