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Kris Mattice stepped on stage for his first bodybuilding competition in May, 2016, with high expectations. After four months of twice-daily workouts and a strict diet of chicken, rice and vegetables, the former collegiate golfer had melted 40 pounds off his 255-pound frame. “I was superconditioned and really lean,” says Mattice, 38, from Kamloops, B.C.

Before: Kris Mattice stepped on stage for his first bodybuilding competition after losing 40 pounds off his 255-pound frame.

courtesy Kris Mattice

But after the competition was over, Mattice ate everything he had been craving during his training. A week later, his weight had ballooned by 20 pounds. “It was really disheartening,” he says. “And it starts a vicious cycle.”

That cycle of dropping dozens of pounds, only to gain most or all of them back again in a relatively short amount of time, is familiar to bodybuilders and anyone who’s tried to lose weight on a low-calorie plan, such as a crash diet, that is not sustainable for longer than a few weeks or months.

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But this cycle, it seems, isn’t about a decrease in will power. Instead, it may have more to do with how our bodies react to the weight-loss process. When people cut calories, they alter the speed of their metabolisms and their hunger levels, making it easier to gain the pounds back, says Kevin Hall, who studies weight regulation at the National Institutes of Health in Maryland.

One of the most famous examples of this phenomenon comes from a study that tracked contestants on the reality show The Biggest Loser, which puts participants through rigorous dieting and exercising for about 30 weeks to see who can shrink the most. The researchers found that most people regained a significant amount of what they had lost six years after exiting the show. A few even ended up heavier than they had been before they started.

This is because during the course of their extreme weight loss, their metabolisms and appetites changed considerably, Hall explains. The contestants’ resting metabolic rate slowed down much more than the team expected – by about 300 calories a day. Even after they regained the weight, their metabolic rates did not go back up: Their bodies continued to burn less calories per pound.

Research shows this phenomenon can happen to anyone, not just those on low-calories diets. For every kilogram of weight loss a person experiences, their metabolism slows down around 20 to 30 calories, Hall says. But while they’re burning less, the body also wants to eat more – the appetite of someone losing weight increases, making the person want to consume about 100 calories more than they were having before.

That’s because the body wants to fight weight loss, says Brad Schoenfeld, a New York-based former bodybuilder and now researcher who focuses on the mechanisms of muscle hypertrophy (the process of maximizing muscular gains while minimizing body fat.)

courtesy Kris Mattice

The process is called adaptive thermogenesis, and it happens, Schoenfeld says, because the body has a certain amount of fat – a “set point” – that it is comfortable with from a survival standpoint and wants to maintain. When a person begins vigorous training combined with a restrictive diet, the body responds by thinking it is under threat. The training increases the body’s muscle mass. But when the diet becomes too restrictive – which varies from person to person – leptin, the satiety hormone, begins to drop, kind of like a starvation alarm.

“It manifests itself as hunger. Or you don’t get as full from your meals, or you can’t go as long between meals without getting hungry,” Hall says.

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An obese person, for example, trying to lose a certain amount of weight has already settled into a very high body-fat set point, Schoenfeld says. So when they start dieting, the body responds to a threat and its appetite increases. And the metabolism slows down.

“The body says, ‘Okay, I like being about 35-per-cent body fat,’ you get down to 30 per cent, you get down to 25 per cent, all of a sudden the body says, ‘We’re in a famine now’ and how does it try to conserve fat? Your metabolism is responsible,” he says.

So keeping the weight off over time requires major will power – and sometimes more effort than it took to lose the weight in the first place.

Most people hit a plateau about six months after following a diet and exercise plan, according to Hall, and depending on where they end up, they are still putting in a great deal of effort to stick to their respective program.

The difference, it seems, comes from the changes in how the body is burning the calories it takes in. According to Hall, discrepancy between the contestants on The Biggest Loser that gained weight back and the group that maintained about a 25-per-cent loss was that the latter group continued with their above-average exercise regimen, while the former did not.

“During active weight loss, the diet seemed to be more important than physical activity. But to keep it off, the situation was reversed. It was much more important to be physically active,” Hall says. “You still have to focus on doing something with your diet, but that didn’t explain who was successful or unsuccessful at keeping it off.”

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Photo courtesy Kris Mattice

courtesy Kris Mattice

The problem is how much physical activity a person needs to keep off the weight. According to Hall and his research, a regular sedentary person who has lost some weight needs to partake in about 80 minutes of moderate exercise – or 30 minutes of vigorous activity – every day, seven days a week to maintain that loss, and make up for a slower metabolism. But that’s much higher than the recommended amount for Canadians of about two and a half hours a week.

This then raises the question: Is there something that you can do to increase your metabolism?

The simple answer, Hall says, is no. At least not in the short term.

“Most of the promises that we see of some special diet being able to boost metabolism … we look at such claims with a high degree of skepticism,” Hall says.

This is because the relationship between weight loss, metabolism and hunger levels is complicated and can vary based on the person’s genetics. Fifty per cent of the variability in body size between people is due to genetics, Hall says, and that can explain resistance to weight loss in certain environments that are not as active. Why one person’s metabolic rate may slow by larger level when they cut calories while another person’s does not is “probably a genetics factor,” but it is part of further research the National Institute of Health is conducting.

In general, in order to lose weight – and keep it off – Hall recommends understanding the importance of physical activity. That doesn’t mean going to the gym every day, but maybe being a more active commuter or taking part in a weekly sport.

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“You have to keep this up for a very, very, very long period of time and be happy doing it because you don’t want to be miserable for the rest of your life,” he says.

When Mattice began preparing for his second competition, he tried something different: He followed flexible dieting, which focuses on counting and tracking macronutrients (proteins, carbohydrates and fats) to achieve a body composition goal rather than just overall calories. Mattice could eat more foods outside of just chicken, vegetables and rice – and enjoyed a bowl or two of cereal, his favourite treat – without it destroying his goals.

When he stepped on stage, he weighed around 218 pounds, but instead of gaining 20 pounds afterward, Mattice was around five to 10 pounds heavier five months post show. He says he didn’t have any strong cravings like he did the first time.

“After my first show, I was kind of a miserable jerk. [This time] I was thinking, I may not come in as good of shape maybe, but I’ll still be myself.”

MAY, 2016

MAY, 2017

235

pounds

225+/–

pounds

218

pounds

215

pounds

Gained

5-10

pounds

Gained

20

pounds

Competition

weight

Post

competition

weight

Competition

weight

Post

competition

weight

TRISH McALASTER / THE GLOBE AND MAIL

MAY, 2016

MAY, 2017

235

pounds

225+/–

pounds

218

pounds

215

pounds

Gained

5-10

pounds

Gained

20

pounds

Competition

weight

Post

competition

weight

Competition

weight

Post

competition

weight

TRISH McALASTER / THE GLOBE AND MAIL

MAY, 2016

MAY, 2017

235

pounds

225+/–

pounds

218

pounds

215

pounds

Gained

5-10

pounds

Gained

20

pounds

Competition

weight

Post

competition

weight

Competition

weight

Post

competition

weight

TRISH McALASTER / THE GLOBE AND MAIL

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