If you’re worried your metabolism will slow – or already has – and that’ll lead to unhealthy weight gain, stop fretting.

Turns out, you have much more control over metabolism than you ever thought. And the long-believed theory that our ability to burn calories and fat diminishes with age is practically a myth, according to extensive research published in Science.

What is metabolic rate?

Your metabolic rate – what we usually refer to as our metabolism – is the rate your body burns calories to keep you alive and functioning. Ideally, you take in the right number of calories to physically and mentally function well while maintaining a healthy weight.

But it’s generally been accepted that as we age, our resting metabolic rate slows, especially once we hit 40. So we naturally burn fewer calories – and then are inclined to gain weight if we continue to consume the same as we did when the metabolism was faster.

Not what we thought

But the study, “Daily energy expenditure through the human life course,” found metabolic rate barely changes throughout life, even as you age in place.

In fact, most people’s metabolism holds steady between the ages of 20 and 60. After than, it drops less than 1% each year. What’s more, the researchers didn’t see a significant difference between men’s and women’s resting metabolic rate, disproving the notion that menopause messes with women’s metabolism even more.

The hard truth on metabolism

So why do many people tend to gain weight or lose overall fitness as they age? In a word, lifestyle. Our metabolism doesn’t slow down. We do.

The resting metabolic rate doesn’t change (much), but what we do when we’re not resting does tend to change between 20 and 60. We sit at desks more, idly look at screens more, exercise less and generally move less. That also leads to losing energy-burning muscle mass, which further slows the calorie burn.

But there’s good news here. You can make changes that have positive effects on your metabolism and overall health. That’s regardless of age, researchers say.

Here are five research proven ways to boost or reset your metabolism.

1. Move throughout the day

While it’s important to get plenty of steps in each day – the current recommendation is 8,500 – it’s even more helpful to spread the activity throughout the day, rather than in just one long bout.

So, yes, get your daily dose of exercise. But make sure you get up and walk around throughout the day, especially if you tend to sit (at a desk, on the couch, at a table, etc.). Many fitness watches can be programmed to give reminders to get up and walk a few minutes every hour or so. You might just set timers on your personal devices to do the same.

2. Sleep well

Although sleep is literally resting, it plays a critical role in good metabolism. People who only get five hours of sleep a night reduce fat loss, according to University of Chicago researchers. Also, sleep deprived people tend to carry about five to 15 extra pounds of belly fat.

The better bet: Get about eight hours of good, deep sleep a night. To sleep better, avoid screens an hour before bed and keep your room dark.

3. Mix up workouts

Mix up your exercise routine, and include strength training. Researchers found HIIT – High Intensity Interval Training – and strength training sessions have the most positive effects on metabolism.

A few days a week, try HIIT – short periods of exercising with an elevated heart rate alternated with recovery periods, which elevates metabolic rates long after the workout ends. On other days, do a regimen of strength training. That’ll build muscles, which increase fat burn.

4. Eat well

Some people think they need to consumer fewer calories to ward off the supposed slow in metabolism. But now you know your metabolism doesn’t slow down significantly. So you want to fuel your body with enough calories and the right kind of nutrition.

Eating fewer than 1,000 calories a day actually slows the metabolic rate, studies have found. Talk with your healthcare provider about the number of calories you should consume daily. And when you determine the baseline, increase the healthy proteins – such as lean meats, fish and nuts – which boost energy and increase fat burning.

5. Drink more

Your body needs water to process calories. Your metabolism will slow down if you’re dehydrated.

So drink more, and try to stick with water mostly. Skip sugary juices. Limit alcohol. Also, snack on fresh fruits and vegetables which have a natural water content.