When it comes to weight, we all know the maths: do more, eat less and lose weight; do less, eat more and gain weight. But is it really as simple as that? Below, sports therapist Katie Hiscock talks us through calories and how to count them.


Next, read up on the best exercises to burn fat and how much protein you need to build muscle. Plus, find out 10 reasons you're not losing weight when exercising.

What's in a calorie (kcal)?

A kcal is a unit of energy contained in food and drink. UK guidelines currently advise an average of 2,000 calories per day for women, 2,500 calories for men and 1,800 for children aged 5 to 10. These guidelines help steer us in the right direction, but they are approximate figures as they can vary based on your age, your lifestyle (for example, how active you are) and your size.

There are also other factors that can also influence how much energy you use in a day including your hormones, certain medications such as steroids, or if you are unwell.

If you're keen to find out a more accurate figure you need to work out your total daily energy expenditure – there are numerous tools available to help you calculate this online.

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Generally speaking, how many calories your body really uses each day depends on a number of key factors:

• age, height and sex
• your basal metabolic rate (BMR) – the number of calories you'd burn even if you stayed in bed all day
• the amount of lean muscle mass you hold – lean muscle burns calories faster, even at rest
• the activities you do – a minute of running is rarely the same as a minute of cycling (see the list below to see calorie expenditure by sport)
• how much you push yourself in the activities you do – the more you sweat and struggle to catch a breath, the more calories you'll be burning

In reality though, a body builder or well-trained athlete may need three times as many calories as the 'average' person a day just to maintain their weight, because of their increased muscle mass and the amount of time they spend training, and that can be up to 6,000 kcal for some!

Group of people running

Try to move more

Exercise builds muscle, and muscle is the body's most efficient calorie burner. We also know that an active lifestyle is good for our overall health, not just our weight, and helps reduce the risk of conditions including type 2 diabetes, heart disease and dementia.

If you want to increase your energy levels, this doesn't necessarily mean entering next year's marathon. Walking the dog for 10 minutes longer each day or hoovering the stairs that bit more rigorously all counts. Here's what that slice of cake equates to in activity terms...

Aerobics for an hour: 533 calories
Rowing for an hour: 438 calories
Running for 30 mins at 7.5 minute miles: 420 calories
Running for 30 mins at 12-minute miles: 303 calories
Skiing for an hour: 314 calories
Swimming for an hour: 423 calories
Slow walking for an hour: 204 calories
Leisurely cycling for an hour (10mph): 292 calories

(Estimated calorie expenditure based on a person with a weight of 72kgs)

Understanding more about calorie counting

When it comes to calories in our food it breaks down as follows:

  • 1g protein = 4 calories
  • 1g carbohydrate = 4 calories
  • 1g fat = 9 calories

Now this appears straightforward if you are following a calorie-counted diet but just tracking calories alone does not take into account the nutrient density of individual foods.

For example, 100 calories of nuts are very different to 100 calories of chips. Nuts are high in protein and good fats which means they will fill you up for longer and can help you eat less across the day, as the body naturally takes longer to turn protein and fat into energy (also known as blood glucose). Chips, on the other hand, are mainly carbohydrates which means the body can convert this into energy much quicker and you could find you end up feeling hungry again sooner as the body uses this energy at a faster rate.

Following a strict calorie count also doesn’t allow you to tune into your natural hunger signals, so you may end up eating less food than your body needs some days, and more on others.

So, the key is to focus on whole, minimally processed foods that are high in protein, fibre and healthy fats as these foods will increase satiety and mean that you will naturally eat less calories across the day, without necessarily having to track them. While calorie counting may help with weight loss, you can’t eat yourself out of a bad diet, and for healthy, sustainable weight loss you need to look at how much you move and what you eat together.

Because exercise builds muscle and muscle is the body's most efficient calorie burner, keeping active can be a better way to watch your weight than shunning scones and dodging doughnuts.

Want more like this? Try...

What is the healthiest exericse?
What to eat before a run
What to eat before cycling
What to eat before a swim

Do you have a specific health question? Ask us in the comments below.

Katie Hiscock is a fitness writer with diplomas in personal training and sports massage therapy. With an interest in sports nutrition, antenatal exercise and injury prevention, she works as a therapist for Brighton & Hove Albion


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 health care professional. If you have any concerns about your general health, you should contact your local health care provider. See our website terms and conditions for more information.

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