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How to speed up your metabolism

14 October 2020

We look at some frequently asked questions about metabolism, and discover the lifestyle changes you can make that will help increase your basal metabolic rate.

BMR is increased by activity
BMR is increased by activity

In this article:

What is metabolism?
Basal metabolic rate explained
What determines your metabolism?
Do men have a higher metabolism than women?
Could an under-active thyroid slow your metabolism?
Does age affect metabolism?
Exercise and metabolism
Foods that increase metabolism
Does exercise speed up metabolism?
Dieting and your metabolic rate
Tips for speeding up your metabolism

What is metabolism?

Bodily functions such as digestion, the beating of your heart, the working of your lungs and all the activities you do in the course of a day all need energy. Metabolism is the process by which nutrients in the food we eat are broken down in our cells to produce energy for these function. But when people talk about metabolism what they usually mean is their basal metabolic rate or BMR, which is the number of calories (or units of energy) that your body burns over a set period of time.

Basal metabolic rate explained

Your Basal Metabolic Rate (BMR) is the amount of energy you use just in existing – lying down, doing absolutely nothing. For most people this accounts for about 60% of their total calorie usage.

BMR is increased by activity – sedentary people increase their daily BMR by around 15% while active people can increase it by 50%, or even more.

Lastly, your metabolic rate is increased by dietary thermogenesis – meal-induced heat production (and therefore calorie usage) caused by the action of eating, digesting, absorbing and using food. This counts for around 10% of our total use of calories.

What determines your metabolism?

Metabolism is controlled by the thyroid gland in the neck, which in turn is governed by a part of the brain called the hypothalamus. The speed of your metabolism depends on complex chemical messages, which are sent to your brain by your body, telling it how much it needs to keep going. Your body size and composition determine how much food you need to produce energy. The heavier you are the more energy your body needs to keep going, so the higher your metabolic rate.

This means that, contrary to popular opinion, if you're overweight you'll have a faster metabolism than someone who is slimmer - a big body like a big car needs more fuel.

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Do men have a higher metabolism than women?

The make-up of body tissue is one of the key things that affects metabolism. Lean body tissue or muscle is more 'metabolically active' than fat, which means it burns more energy, even when you are at rest. This is why men, who naturally have a higher ratio of muscle to fat, tend to burn up what they eat faster, although a fat man may have a slower metabolism than a slim women with more muscle tissue.

Could an under-active thyroid slow your metabolism?

If the thyroid isn't producing enough hormones it can slow down metabolic rate, although only by a small amount. But unless your thyroid is extremely underactive - in which case there would be other clues such as extreme fatigue, depression, dry skin and hair and a loss of sex drive - it's unlikely to be to blame for weight gain. And once you get any underactivity treated it will return to normal.

Does age affect metabolism?

Metabolism slows down slightly with age, as a result of us having less muscle tissue as we get older, but only marginally. So a 70kg man who stayed the same weight throughout life would need four to five per cent less energy at 50 to maintain his weight and 10 per cent less by the age of 70, which is why you need to eat slightly less or exercise slightly more as you get older.

Does exercise speed up metabolism?

Increased activity levels can increase metabolic rate because you breathe harder and your heart rate increases, which causes a demand for more energy. Any exercise, however, has to be really vigorous to make a significant difference and your metabolic rate soon reverts to normal as your heart rate recovers.

The good news is that regular exercise - especially weight-bearing activities such as working out with free weights, weights machines at the gym or classes such as Body Pump - builds muscle and the greater your muscle mass, the higher your BMR.

Foods that increase metabolism

The NHS has this official line on metabolism-boosting foods: ‘It's claimed that certain foods and drinks can boost your metabolism, including green tea, black coffee, spices and energy drinks. The evidence behind these claims is weak.’

However, many leading researchers and research studies are coming to different conclusions, and it may well be worth including more of the following foods in your diet to help boost your metabolic rate.

  • All high-protein, low-carb foods. Research shows the thermic effect of eating protein is 20-35%, compared with the total food average of 10%. High-protein foods include fish, poultry, lean meat, eggs and hard cheeses. Pulses, particularly soya, and nuts are also relatively high-protein foods. Therefore a moderately high-protein diet is worth considering.
  • Chillies have been shown in several international experiments to increase MR by up to 50% for 2-3 hours after eating, and this appears to be because the heart rate is increased by the chemical capsaicin that they contain. Some other spices, including turmeric, cinnamon and ginger, may also have a thermal effect.
  • A very recent overview of the studies on caffeine and weight control concludes that it does, indeed, help to boost metabolism. Research published in The American Journal of Clinical Nutrition has found that drinking coffee, which is rich in caffeine, significantly increases MR for up to 3 hours. Teas, including standard black tea, matcha tea and green tea, which all contain caffeine, have also been shown to boost MR.
  • In addition, there is some evidence that drinking half a litre of water before a meal can raise your metabolic rate at least in the short-term, but studies affirming this are limited. It can, however, help you to eat less, so may be worth trying in any case.

There have been some small studies linking fish oils and other healthy fats, nuts and vitamin-D (from sunlight and fish such as salmon and herring) to increased metabolic rate, but there is little proper scientific evidence to prove this. However, all these foods have various health benefits – and a general healthy diet with more of these foods and fewer ‘junk’ foods will almost undoubtedly help to regulate weight.

Dieting and your metabolic rate

Very low-calorie, rapid weight-loss diets can slow down your metabolic rate if followed for more than a very short time. What happens is that your body begins to use more muscle for energy and, as we’ve seen, the lower your muscle mass, the slower your metabolism.

Losing muscle mass also means that once you come off the diet, you’ll put the weight back on more easily because of your slow metabolic rate. So if you want to maintain a good MR, don’t diet too quickly!

Even if you lose weight slowly, it is common for people who have lost weight to permanently need to eat fewer calories than they did when overweight, because their metabolic rate has naturally slowed down alongside the weight loss. This is because a slim body has less work to do than a heavy body (because there is, quite simply, less weight to carry around), so it uses less energy. Increasing your muscle mass (see below) is a simple way to counteract this natural effect.

How to speed up your metabolism

According to research, most people have very similar metabolisms and an individual’s size is only rarely down to metabolic rate.

However, because overweight people have larger bodies, their bodies ‘need’ more calories for processes such as respiration, cell production and repair, as well as digesting food. Regardless of this, there are some lifestyle choices you can make to boost your metabolic rate.

1. Build muscle to boost your metabolism

The cells in your muscles have to work harder than those in fat cells so, by adding muscle, you can increase your basal metabolic rate (BMR). This is what people are referring to when they say ‘metabolism’ – how quickly you use up calories.

Our muscles are very much more metabolically active than any other component of our bodies and so they burn up more calories just by being there! However, without regular use their size diminishes and the metabolism-boosting effect wanes. The main way to maintain muscle is to do resistance exercises – either with free weights, by using gym equipment or your own body weight to create resistance.

2. Cut some calories to increase your metabolism...

As you age, you tend to lose muscle mass and gain fat, which means your BMR slows down, ie you no longer burn fuel as quickly as before. To address this issue, you’ll need to eat fewer calories than you used to if you want to maintain the same weight or figure. Cut down on sweet or carbohydrate-rich foods but keep up your intake of lean protein, low-fat dairy and fresh vegetables and fruit. That will help maintain muscle mass and bone strength, while reducing your calorie intake.

3. ...But don’t cut too many calories, or you could slow your metabolism down

Dramatically restricting your calorie intake could actually slow your metabolism down. That’s because when you go on a crash diet, your body starts to break down muscle mass, which in turn means fewer muscle cells using up calories. So when you diet, reduce your calorie intake by only 300 calories a day. You’ll lose weight more slowly than on a crash diet, but you’re more likely to stick to it and your metabolism won’t suffer as a result. Protein in the form of eggs, cheese, yogurt, or baked beans, along with fresh fruit and wholegrain toast will set you up nicely for the rest of the day.

4. Do aerobic exercise to speed up metabolism

Aerobic activity burns calories faster than any other type but to trigger that aerobic process your heart needs to beat faster, so you need to jog, cycle fast or swim at speed. If you’re not sure whether you’re doing aerobic exercise or not, try talking – if you can talk easily, without having to take breaths between words, you’re not going fast enough. Do check with your doctor before changing your exercise regime. If you have health problems, follow your GP’s or specialist’s advice, and don’t do more than your body can cope with.

It is advisable, especially as you get older and/or have medical problems, to get advice on what exercise is best and safest for you from an expert – start with your GP.

5. Lift some weights to boost your metabolism

As you age and your strength begins to diminish, it’s easy to let others help you and so lose even more muscle mass. But don’t worry, it doesn’t mean you need to carry your own suitcases all the time – in fact, carrying heavy loads like this when you’re not used to it could cause you an injury – it simply means you need to include strength-training in your weekly exercise regime. Use resistance bands to work out at home or the gym, or buy some simple wrist and ankle weights to use while you walk, for example.

6. Drink green tea to increase your metabolism

While studies haven’t been able to definitively prove green tea’s metabolism-boosting benefits, there is some evidence that epigallocatechin, a substance in the tea, can stimulate metabolism. Whether or not there’s enough of it in a cup of green tea to make a difference isn’t certain, but as green tea is full of antioxidants too, it certainly won’t do you any harm to drink it.

7. Keep your home cool for a faster metabolism

Research shows that people who live or work in overheated places (all other factors being equal) have lower metabolic rates than people who are in cooler conditions. Being cool helps to boost our levels of brown fat, a special type of fat that increases the metabolic rate. Some people need to keep warm for medical reasons, but others could consider turning the central heating down a little, or wearing one less jumper. 

Discover the foods most likely to help you burn fat

8. How red grapes help your metabolism

Resveratrol, found in the skins of red grapes, has been associated with all kinds of health benefits, and some studies have linked it with improvements in aspects of metabolism such as lower blood sugar and pressure, as well as decreased liver fat. The jury’s still out on whether it actually helps speed metabolism so instead of drinking red wine to get your resveratrol, which will add empty calories to your diet in the form of alcohol, sip on red grape juice or even better eat the real thing – that way you’ll be enjoying the benefits of healthy fruit at the same time.

Find out more about the role of antioxidants in your diet

9. Fidget to increase metabolic rate

There is plenty of research to show that fidgeters burn up hundreds more calories a day than non-fidgeters, and raise their MR without thinking about it. Small movements, from foot tapping to moving in your chair and even laughing can all produce what is termed NEAT (or non-exercise activity thermogenesis).

Building small things into your daily life could add up to a good increase in your MR. Stair-climbing is brilliant, so try never to take a lift. Gardening, particularly digging and mowing, and housework, such as window cleaning, are good, too. The less you sit still, the more you’ll boost that metabolic rate.

Just switching from lying down to sitting up, or switching from sitting to standing will make a difference.

10. Get plenty of sleep for a faster metabolism

Insomnia on a regular basis can slow your metabolism according to a large overview of all the studies on the subject. If you suffer from insomnia, one of the best ways to help overcome this is to do more exercise and try to take much of it outdoors. Relaxation and breathing exercises can also help, as can reducing alcohol intake.

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