Lose the weight, keep the muscle
Study seeks best combination of diet, exercise for ‘high-quality’ drop in pounds
The new discussion around weight loss doesn’t judge success by the numbers on the scale.
Instead the focus is on losing inches without losing muscle, a combination that’s hard to achieve by cutting calories alone.
Why is maintaining muscle so important? Contrary to fat, which stores energy, muscles burn calories, which makes it a key player in keeping lost weight from coming back.
It also preserves functional strength, which makes the chores of everyday life easier to accomplish. Yet traditional diets have been known to reduce lean body mass by 20 per cent to 30 per cent.
The trouble with relying on both exercise and diet to lose unwanted weight is that both variables can be manipulated in thousands of ways.
The Exercise Metabolic Research Group from Hamilton, Ont.’s, McMaster University has been actively searching for the most effective combination of diet and exercise with their latest study bringing them one step closer to defining strategies for what Dr. Stuart Phillips, member of the Exercise Metabolic Research Group and Canada Research Chair in Skeletal Muscle Health, calls “highquality weight loss.”
The McMaster team divided 25 moderately active young men into two groups and manipulated their dietary and exercise habits for four weeks to see if they could get in shape, lose weight and preserve or gain muscle mass.
Each of the men was provided with pre-packaged meals individually designed to disrupt energy balance by a reduction of a whopping 40 per cent fewer calories daily.
Group 1 consumed 15 per cent of their calories from protein, 50 per cent from carbohydrates and 35 per cent from fat. Meals for Group 2 were made up of 35 per cent protein (three times the recommended daily allowance), 50 per cent carbohydrates and 15 per cent fat.
The protein was administered throughout the day in meals and in liquid form with one drink reserved for immediately after exercising. Neither group was aware of whether they were consuming the high- or low-protein diet.
As for the exercise, the young men reported to the gym six days a week where they performed a weighttraining circuit twice a week, a HIT (high-intensity interval training) workout twice a week, an aerobic workout on the bike once a week and a plyometric (jump training) circuit workout once a week.
In addition they were asked to accumulate 10,000 steps on days they weren’t in the gym.
At the end of the four weeks, it wasn’t surprising to discover that both groups lost a substantial amount of weight.
What was surprising: despite similarities in the amount of weight lost, the composition of lean body mass differed substantially between the two groups.
The low-protein group saw no change in muscle mass while the high-protein group added 1.1 kilograms of muscle to their frame.
As for fat loss, once again the highprotein group posted better numbers, losing 1.3 kilograms more fat than the men who consumed less protein.
Gains in fitness and strength were substantial but not significantly different between the two groups.
Surprised by the results, the McMaster team noted that similar studies haven’t yielded the same success at increasing muscle mass when calories were reduced and exercise (usually weight training) added. In fact, most reported either maintaining or experiencing a small loss of muscle under similar conditions.
The researchers suggest the reason for the difference lies not just in the amount of protein consumed by the young men in the McMaster study, but also in the timing of the protein (immediately after exercise) and in the type of exercise prescribed (strength training complemented with short high-intensity intervals).
Before you go out and try to replicate this experiment, it’s time for a reality check.
The diet and exercise routine assumed by both sets of study subjects is more like the gruelling regime featured on The Biggest Loser than that of the average Canadian.
“It wasn’t meant to be sustainable,” said Phillips of the protocols followed in the study. “It was designed to prove a concept.”