Does exercise really influence weight loss?

Candice Chung
Wednesday, April 13, 2011

Nothing beats a good work-out when it comes to fighting the flab, right? But what if we told you exercise alone is basically "useless" at helping you lose weight?

In many ways, exercise has become the new religion for modern urbanites. We take our cardio sessions seriously, devote our free time to the local gym and pay our penance on the treadmill after indulging in delicious, sugary sins.

It's a tough gig, yes — but we do it anyway in the hope that one day we will shed those extra kilos and kiss our "muffin top" goodbye.

You move, you lose?
Despite the common assumption that hours of physical training will lead to faster weight loss, a growing number of UK and US studies have found this simply isn't the case.

A new study published in the New England Journal of Medicine showed that exercise alone is not enough to make you slim. To investigate the effectiveness of diet versus exercise, researchers tracked the weight of 95 obese adults over the age of 65 over a one-year period.

The subjects were split into four groups: control, exercise only, diet only and a combination of diet and exercise. Surprisingly, the "exercise only" group did no better than those who made no change to their lifestyles — neither group lost any weight by the end of the trial.

These findings echo the sentiment of renowned US exercise researcher, Dr Eric Ravussin, who recently told Time that, "In general, for weight loss, exercise is pretty useless."

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The 'compensation effect'
So what exactly accounts for the disappointing results? According to Graham Park, author of 7 Secrets the Weight Loss Industry Will Never Tell You, the answer is fairly simple.

Strenuous exercise will stimulate strong hunger — the resulting fluctuation in blood sugar causes us to eat more and negates any kilojoules we may have burned.

"Your appetite is geared to your energy expenditure every day," Park says. "So if you go out and burn 1000 calories by running, you're likely to eat an equivalent number of calories to make up for it."

Combine this with the "compensation effect"— where people feel the need to reward themselves after a particularly gruelling gym session — the hard work is basically undone.

"People often think they've 'earned the right' to indulge after working out," Park says. "But if you have a pie and a beer after a gym session, you'll have to jog for over an hour to burn it off — most of us would never do it."

What's more, researchers have found that those who engage in vigorous exercise during the day may also compensate in another way by being more sedentary in their downtime — meaning their net energy expenditure would end up being little more than a normal, gym-free day.

The 80:20 rule
Given the "compensation effect" of strenuous exercise, Park believes the most effective way to trim our waistlines is to clean up our diet first. The formula to successful weight loss, according to Park, is "80 percent diet and 20 percent exercise" — at least to begin with.

Professor Jennie Brand-Miller, expert nutritionist from the University of Sydney and president of the Glycemic Index Foundation, agrees. "You only have to consume 50 calories extra a day to be a few kilos heavier at the end of the year. We're talking about the equivalent of half an apple or half a slice of bread a day." Put simply, it's much easier to skip that extra Tim Tam than to walk an hour to burn it off.

The key, Professor Brand-Miller says, is not to deprive yourself — but to realise that "not all calories are equal" when it comes to their impact on our appetite. She recommends following guidelines from the world’s largest diet study, Diogenes: "Eat plenty of low-GI foods that will make you feel fuller for longer and include protein and 'good fats' [such as nuts and avocado] in your diet. This combination is the easiest way to maintain weight loss."

The importance of exercise
If exercise is deemed "pretty useless" for shedding the kilos, then is it time for us to renounce our faith in the gym? Actually, no — not quite. Because here's the caveat: while exercise alone is not the magic bullet, it is a powerful game-changer when combined with the right diet.

In the New England Journal of Medicine study, the group that focused on both exercise and diet performed the best overall, losing 9 percent of body weight while retaining lean body mass.

"Exercise not only benefits our bodies but our minds. We feel better when we exercise and a healthy headspace is fundamental [when it comes to] weight management," celebrity personal trainer Michelle Bridges says. "There are so many amazing benefits from exercise — [including] increased longevity, mobility and energy… [It] also builds lean muscle and increases muscle insulin sensitivity."

Richie Garard, personal trainer and owner of She Fitness outdoor training group, adds that regular exercise also plays a vital role in keeping the weight off. "Once someone has gone through a successful weight-loss journey, it can be hard for them to maintain the same level of commitment."

Continuing to work out will "rev up" our metabolism, helping us keep those dreaded love handles at bay.

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