• Our genetics play a big role in how easy we find it to gain and lose weight. 
  • But it's possible to be a healthy weight despite your genes, an expert in the genetics of obesity said.
  • His weight loss tips include finding the right diet for you and focusing on health over appearance. 

Losing weight and keeping it off is tough, but just how tough depends on your genes, according to a scientist who studies the genetics of obesity. But it's still possible to make healthy changes to your body even if your biology predisposes you to habits such as overeating.

A person's genetics are probably the biggest influence on why and how much a person eats, professor Giles Yeo, principal research associate at the University of Cambridge Institute of Metabolic Science, told the Just One Thing podcast on January 3.

Our biology impacts body weight in multiple ways, from giving us a preference for sweet treats versus veggies to suppressing or ramping up our appetites when stressed out or making one person require more food to feel full and satisfied than another.

All of these factors mean that losing weight is a lot harder for some than it is for others.

But, Yeo said: "Your genes do not determine who you are. They set a set of possibilities, but you can do something about it."

Yeo shared four tips for healthy, sustainable weight loss, regardless of your genes.

Find a diet that you can stick to

Yeo's top tip for losing weight is finding a diet that's healthy and you can stick to.

"There are diets which work very very well for some people but have absolutely no effect on other people. Or other people can't stick to them," he said.

Any diet that allows you to absorb fewer calories will get you to lose weight, he said, but he recommended most people try and eat more protein, a lot more fiber, and fewer refined carbohydrates.

His recommendation mirrors the Mediterranean diet, which has been voted the healthiest way to eat by US News & World Report for seven years in a row.

Don't focus on calories alone

To lose weight, you have to be in a calorie deficit, meaning you're burning more calories than you consume. But what you eat matters even more because calorie counts on packaging can be misleading, Yeo said.

Calories can tell you how much energy is in a food or drink, but nothing about its nutritional value, which is important, he said. For example, 200 calories of protein will keep you feeling full for much longer and provide you with more nutrients than 200 calories of a chocolate bar high in refined sugar.

Equally, the amount of calories the body absorbs differs depending on what we've eaten. Yeo explained that the body extracts fewer calories from protein than sugar because it's more chemically complex and takes more time to digest. "Protein calories are 30% wrong everywhere," he said on the podcast.

The way that food is prepared matters, too. The body is able to absorb more calories from corn, for example, if it's broken down and made into a tortilla than if it's eaten straight off the cob, Yeo said.

Exercise doesn't really help you lose weight

Although excellent for our overall health, exercise is actually not a very good weight-loss tool, partly because it's hard to burn off a significant amount of calories, and it also leaves you feeling hungry, Yeo said.

Research suggests working out makes up only about 5% of the energy we burn in a day, while the rest mostly comes from simply living. It can however be beneficial in helping you keep weight off once you've lost it.

This is because when you lose weight, your metabolic rate — or the amount of energy your body needs to perform basic functions —drops, but when you exercise, it temporarily rises again. "So it begins to increase your metabolic rate at least temporarily during the day, which takes away some of this effect of the weight loss metabolic rate drop," Yeo said.

If you find that exercise reduces your stress levels, he said, it may also help you keep off weight if you're someone who's likely to reach for food when worry hits.

Focus on your health over your appearance

People want to lose weight for lots of reasons but a common motivation is to fit into societal beauty ideals. This can prove to be a weak motivator in the long run though, and doesn't necessarily benefit your health, Yeo said.

Instead, he thinks we should all try and focus more on our health and the many tangible benefits of healthy eating and exercise, such as improved mood, better sleep, and higher energy levels.

"If you take care of your health, your weight will take care of itself," he said.