Is it really as straight forward as calories in vs calories out?

You may have heard the saying that weight loss is merely a case of “calories in vs calories out” – if only life was that simple! Calories in food is only part of the picture when it comes to wellbeing and weight management. The effect that food has on your metabolism is also meaningful for health and prevention of diseases such as obesity and diabetes.

Here, I review foods which have been shown in scientific research to boost metabolism to support your body in utilising energy and maintaining a healthy weight.

What is metabolism?
Metabolism refers to biological processes within the body which help to keep you alive and functioning properly. Metabolism ranges from supporting activities in your cells, helping to break down foods into their bioavailable forms and acting as a waste disposal unit – eradicating troublesome compounds from the body.

Metabolism is often described interchangeably with metabolic rate, which refers to the number of calories your body burns in a period in order to maintain proper metabolism. The higher the metabolic rate, the easier it is for you to burn calories and lose weight.

Certain foods help to increase metabolic rate due to their thermic effect. The thermic effect of food refers to the energy required to digest, absorb and utilise the food – this squashes the calories in vs. calories out theory, which only considers the number of calories in the food itself. Other foods provide nourishment to support metabolism, which ensures that these processes run efficiently and robustly.

Which foods enhance metabolism?

Protein-rich foods
Protein-rich foods have been shown to have the highest thermic effect, as they require the most energy to break down in comparison to fat or carbohydrates. To aid metabolism, it is suggested to include protein at every meal to increase the thermic effects which will help with weight management.

Thyroid-supporting nutrients
The thyroid gland produces hormones which keeps your metabolism under control. If there are shortfalls in nutrients which are needed for the thyroid gland to function properly then metabolism can be altered, either with over- or under-stimulation. Iron, zinc and selenium are key nutrients required for healthy thyroid function. Iron and zinc are most abundant in animal products such as eggs, organ meat and shellfish. The brazil nut is one of the best sources of selenium, with one nut providing at least the recommended daily allowance of selenium.

The heat of the chilli pepper
Capsaicin, a compound found in chilli peppers, has been shown to increase energy consumption and promote fat burning. Studies have shown that consuming capsaicin increases a person’s calorie utilisation by up to 50 calories a day. Capsaicin may also help suppress appetite, so as well as assisting you to burn more calories, it also helps you to consume less food.

The magic of matcha
Green tea has been shown to support immunity and increase metabolism. A compound found in matcha called epigallocatechin gallate (EGCG) has been shown to prevent the growth of fat cells as well as boosting metabolism. Including a couple of extra brews in your daily routine is a simple and effective way to keep your metabolism ticking along at a forceful rate.

When it comes to metabolism, the type of food you are eating is of as much importance as the quantity of calories you are consuming. Food serves much more of a purpose than energy alone, it provides the resources to aid vital biological processes in the body. If there are deficits in these processes, then even in a calorie-restricted state, you may not see the outcome you are hoping for.

So, try eating to lose weight by consuming foods that provide nourishment for your metabolism and boosting it appropriately without depriving yourself of major nutrients that are needed by your body to operate fruitfully.


As featured inside Thrive Magazine Spring 2020 issue. Thanks to #ThriveExpert and Qualified Nutritionist Victoria Hamilton for writing this article.  Victoria is one of our Thrive Experts in Nutrition and holds a BSc in nutrition from Institute of Optimum Nutrition and has a BSc in Biochemistry with Immunology. Find out more from: Victoria Hamilton