Keep off the pounds by outsmarting your DNA

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Natalia Snajdr has always been sensitive about her weight. “I was bigger-boned than the girls I grew up with, and I struggled a lot in high school,” says the 33-year-old Ottawa environmentalist. It didn’t matter whether she took up jogging, windsurfing or tennis — nothing ever seemed to make much difference. Natalia blames her DNA. “Both my parents have strong Eastern European roots, and I have always been what we refer to in Czech as ‘full-thin.’” Now, research shows she may be on to something.

Scientists have discovered that some genes make us more prone to weight gain, while others affect how well our bodies respond to the time we log on the treadmill. But don’t despair: Whether you’re a seasoned yo-yo dieter or a frustrated gym-goer, there are proven techniques you can use to beat your genetic makeup.

Don’t let your DNA get you down
Research suggests that your risk of inheriting a higher body-mass index ranges from 40 to 70 percent — and a lot does depend on your parents. “We know your risk of obesity doubles when one parent is obese,” says Ruth Loos, program leader in the MRC Epidemiology Unit at the Institute of Metabolic Science in Cambridge, U.K. And, she adds, you’re up to five times more likely to struggle with your weight if both parents are overweight.

“This suggests that there’s a familial component in your genetic susceptibility to obesity,” she says. But the idea that a higher risk for weight gain is all in your genes is controversial — and Loos is quick to add a caveat. “The research needs to be interpreted with caution, because we share not only genes with our parents, but also a common lifestyle in the way we eat and how physically active we are.”

That said, there are 32 alleles (different versions of the same gene) associated with obesity, and each one carries the risk of almost an extra pound of body weight. “Although it’s possible to carry copies of 64 risk alleles, very few people — less than one percent of the total population — are that unlucky,” says Loos. “But we can’t tell just by looking at people whether they carry more or fewer risk alleles.” Nor can you tell by taking a trip to the doctor’s office, although researchers are working on it.

In the meantime, should you simply throw in the towel, abandon the treadmill and defer to your DNA? Absolutely not, says Loos. In fact, her research shows that if you’re physically active on a daily basis, you can reduce your susceptibility to obesity by 40 percent. “Thirty minutes of at least mild activity [like] every day is all you need to reach that reduced level of risk,” she says.

The truth about jock genes
For some people, the worst part of a workout isn’t the sweating, the muscle pain or even the struggle to just find time to hit the gym — it’s the fact that they don’t see the results of all the time they spend in spandex. Just as your genes affect your risk of having a higher BMI, they influence how well your body responds to working out. “We have good evidence from twin and family studies showing that there is a significant genetic component affecting how individuals respond to exercise,” says Tuomo Rankinen, associate professor with the Human Genomics Laboratory at the Pennington Biomedical Research Center in Baton Rouge, Louisiana. “The health benefits from exercise are not one size fits all.”

His research identified “low” and “high” responders when it comes to working out: A low responder is someone who doesn’t get the same physiological benefit from exercise as average and high responders, he says. “For example, a 20-week fitness program may increase aerobic capacity by an average of 17 percent in a group of previously sedentary individuals,” he explains. “But those improvements can range from zero percent for a low responder up to 50 percent for a high responder.”

How much you enjoy working up a sweat may also depend on your DNA. “Clearly, there’s a genetic component affecting how active we are and how we respond to exercise,” says Rankinen. “In both cases, we found that genes do play a role, but we don’t know how many are involved or which ones they are.”

The secret to making the most of your DNA
Despite Rankinen’s findings, your genes aren’t a reason to ditch your gym membership. In fact, the opposite is true. “Being a low responder for one trait doesn’t mean you won’t have any health benefits from regular physical activity,” he says. “Even if it’s harder to improve your aerobic capacity with exercise, you will still experience other benefits, including lower blood pressure and higher heart-healthy HDL-cholesterol levels.” And although it may take you longer to see the results you want, the risks of not exercising (including obesity, diabetes and heart disease) are just a few more reasons to lace up your running shoes.

“As with many lifestyle-related diseases, obesity appears to be a classic case of nature and nurture,” says Christopher Schofield, a professor in molecular chemistry at the University of Oxford who has studied the genetic link between genes and body weight. “Both our genetic makeup and our experiences are important.” His advice? Don’t lose sleep over the research.

“The difference between people who are overweight and those who are slim is likely a combination of their genes and, more importantly, their lifestyle habits,” he says. “Although a person’s genes can affect weight, body-mass index and increased risk of obesity, they are only part of the story — lifestyle choices, such as smart eating and regular exercise, are vital to maintaining a healthy weight.”

To reduce your odds of being overweight, you just need to work with the body you have and find a fitness regimen that’s the best fit for you. (Sometimes talking to a personal trainer, a dietitian or even your family doctor can help.)

Natalia Snajdr eventually went to a certified personal trainer for advice. “I learned about the kinds of workouts that I need to do, as well as at what intensity and for how long.” She began combining cardio and weight training five days a week and wore a heart monitor to track the intensity. With the help of a more tailored fitness routine and healthy diet, Snajdr shed 19 pounds and is healthier — and fitter — than ever before. “I always thought it didn’t matter what I did, that I would always be larger because that’s just the way I was born,” she says. “Now, it feels really good to see positive results after all my hard work.”

Training for your body type
Tired of working out to no avail? “If you set realistic goals, personalize your workout and consistently eat well, you’ll notice changes,” says Pam Mazzuca, a Toronto-based personal trainer and athletic therapist. Here’s how to get the results you want with the body type you have.

• Long & Lean: Ectomorph.
  Despite their slender form and low body fat, ectomorphs tend to have a less developed muscular system. “Although ectomorphs don’t need to do cardio training for weight control, it’s still important for heart health,” says Mazzuca.
  Trainer tip: “This body type will benefit from strength training and Pilates to build muscle and improve posture.”
• Strong & Solid: Mesomorph
  Mesomorphs tend to be natural athletes who are highly muscular with large bones and thick joints. “Because mesomorphs respond well to exercise, variety is especially beneficial for them,” says Mazzuca.
  Trainer tip: “This body type builds muscle more easily than the other two types, so it’s important to include stretching and yoga as part of their regular fitness regimen to avoid short, bulky-looking muscles.”
• Soft & Round: Endomorph
  Endomorphs tend to have a fuller shape and can gain weight easily, but they are also adept at building muscle.
  Trainer tip: “Endomorphs should include regular cardio training as part of their routines and train at a higher heart rate to maximize calories burned. Highintensity interval training is great for them. Strength training should consist of total-body exercises with short bursts of cardio between sets for best results.”