If you’re packing on the pounds, you can no longer claim a slowing metabolism. A shocking new study debunks the myth that our metabolism — the rate at which we burn calories — begins to decline as we get older.

A team of international researchers found that our energy expenditure — the more scientific term for metabolism — remains stable from the age of 20 to 60. Seniors over the age of 60 do suffer a decline in metabolic rate, noted the study that was published last week in the journal Science. The scientists studied more than 6,400 people, ages 8 days to 95 years, from 29 countries and found that while infants have the highest metabolic rate, the calorie-burning ability in middle-aged individuals really doesn’t slow down.

“Metabolic rate is really stable all through adult life, 20 to 60 years old,” said study author Herman Pontzer, an associate professor of evolutionary anthropology and global health at Duke University. He told NBC News that there is “no effect of menopause that we can see,” adding that people often blame advancing age for their weight gain as they hit their 30’s and beyond.

According to the New York Post, this game-changing study means we have to search for other reasons for the common complaint of middle-aged spread.

“We have to look at all the reasons your body may have gotten heavier,” said Isabel Smith, a nutritionist in private practice in New York City. “We’ve assumed that it’s because your metabolism has slowed down but actually we have to consider your sleep, your stress, your exercise, your alcohol consumption, your nutritional status and your hormones.”

Dr. Gabe Mirkin, who is board certified in sports medicine, says that the average American gains a pound and a half annually after the age of 30.

“This is long before metabolism begins to slow at age 60,” he says. “So we need other explanations for weight gain during those years.”

Smith says the new evidence means we should shift our thinking away from deprivation and dieting to eating more nutritious foods that fuel our cells.

“That means lots of healthy fats, such as nuts, seeds and avocado, good sources of proteins such as responsibly farmed fish and six-plus servings of veggies a day,” she told the Post.

Fitness expert Mark Koester, director of fitness with Active Wellness at the 92^nd Street Y in New York City, says that along with a healthy eating plan, exercise is important in keeping fit. He encourages a program of cardio, strength and weight training moves to burn calories.

According to the Post, Koester recommends 30 minutes of exercise daily, five days a week. That means walking, biking or another cardio exercise one day followed by strength training the next. Lifting weights, squats, and push-ups are just some examples of strength training moves.