We often hear that what we eat or how much we exercise can speed up or ‘boost’ our metabolism. So is it true? Can what we eat influence our metabolism, and more specifically help us lose weight?


What is metabolism?

Metabolism is the broad term given to all the chemical processes that occur in every cell of our body, to create energy and keep us alive. This includes the conversion of food into energy for vital tasks such as breathing, circulating blood, building and repairing cells, digesting food, and eliminating waste.

Metabolism is different to metabolic rate. Metabolic rate refers to the amount of energy an individual uses being alive. Typically this is measured as the number of calories that the body uses in a day, and is often referred to as our basal metabolic rate (BMR). BMR accounts for 60-80 per cent of our total energy expenditure in a day and includes vital functions like breathing, sleeping and blood circulation. For most of us, physical activity accounts for 15-30 per cent of our daily energy expenditure and a small percentage of energy is used extracting energy from food.

One commonly asked question is ‘can we influence our metabolic rate?’ i.e., can we use food or exercise to speed up our metabolism, so we burn more energy and use up more calories? The short answer is no, it’s not that straightforward.

BMR is hard to change and depends on:

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  • Genetics
  • Muscle mass: muscles are more metabolically active, needing energy to contract and relax, and to repair themselves against daily wear and tear. The more muscle a person has, the higher their BMR.
  • Body size: people with larger bodies have faster metabolisms because larger bodies have more cells.
  • Age: as we age, we lose muscle mass which slows the metabolic rate.
  • Sex: men tend to have more muscle mass than women, so they burn more calories.
  • Hormone disorders: such as Cushing’s syndrome and hypothyroidism can slow metabolism, as can changes to hormone levels during menopause.

Visit our ‘All you need to know about diets’ page for recipes and more expert advice on weight loss, including the benefits of fasting and what’s the healthiest exercise?

How does metabolism affect weight?

Many people blame their metabolism for difficulties losing weight or gaining weight easily. However it is rarely the only cause of weight gain or loss. BMR naturally regulates itself to meet your body’s needs and is ultimately defined by your genes. These differences are evident in how easy or hard it is for people to lose weight.

What is a fast and slow metabolism?

A slow metabolism burns fewer calories, which means more are stored as fat in the body; that's why some people have difficulty losing weight by just cutting calories. A fast metabolism burns calories at a quicker rate, which explains why some people can eat a lot and not gain weight. Let’s not forget that a slow metabolism is not going to be the only factor in weight gain. Poor diet and inactivity will have a greater effect than metabolism alone.

Does metabolism slow down with age?

Research has revealed four distinctive phases of energy expenditure during the lifespan: neonatal, childhood, adulthood and older adulthood (over 60 years). At approximately 60 years old, metabolism starts to slow down, and as people get older, they begin to lose muscle mass which also slows metabolism.

Do women have a slower metabolism?

Sex can affect metabolism due to differences in body composition, fat storage, and hormones. Because of these factors, men tend to have a faster metabolic rate than women. For women, the active form of oestrogen, oestradiol, plays a key role in the regulation of metabolism and body weight. As levels of oestradiol decline during perimenopause and menopause, this can cause some women to gain weight.

Woman doing hiit workout at home

How to speed up your metabolism

There are some factors such as age and genetics that can’t be changed, however you can try the following suggestions to see if they benefit your weight and health goals.

  • Strength training, specifically resistance training and high-intensity interval training (HIIT) can increase metabolic rate and help you burn more calories.
  • Eating regular, balanced meals containing whole grains, nuts, seeds, lentils, plenty of fresh fruit and vegetables and good sources of protein. There is also increasing focus on gut microbiomes and the role they play in our overall physical and mental health. Having a varied diet will ensure you maintain a rich gut microbiome.
  • Avoid ultra processed foods that contain high levels of fat, sugar, salt and additives. They are linked with a higher incidence of overweight and obesity and require less energy to digest which means you will burn fewer calories when eating them.
  • Caffeine in tea, coffee and green tea can increase energy expenditure by a small amount.
  • Sleep can help with metabolic control – so try and get to bed earlier.
Cup of black coffee with coffee beans

Metabolism-boosting food and drinks

So, can you speed up your metabolism for weight loss?

As with most things related to dieting and weight loss, there is not one quick fix, or metabolism booster that is going to significantly increase the amount of calories you burn. Instead, focus on maintaining muscle mass, choosing the right types of foods and paying attention to basics, such as drinking plenty of water and restful sleep.

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All health content on bbcgoodfood.com is provided for general information only, and should not be treated as a substitute for the medical advice of your own doctor or any other healthcare professional. If you have any concerns about your general health, you should contact your local healthcare provider. See our website terms and conditions for more information.

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