Can what food you eat help to speed up your metabolism and lose weight?

Can you really speed up your metabolism by changing your diet? We asked accredited, practising dietitian Melissa Meier if there was truth to this nutrition myth. Turns out the answer is yes, but there’s a catch… 

A slow metabolism is a common culprit when the scales just won’t budge. A quick Google search will tell you to chow down on anything from chilli to coffee to avocado to help you burn calories quicker… but is there any truth to these claims, or is it just nutritional nonsense? Here’s your dietitian-approved answer.

Metabolism 101

Let’s start with a quick refresher. Your metabolism refers to all of the chemical reactions happening inside of your body, day in and day out, that keep it up and running – it’s a bit like an engine.

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Your metabolic rate (i.e. what everyone wants to speed up) is broken into three components:

1. Basal metabolic rate (BMR) – this is the bare minimum amount of energy (kilojoules/calories) your body needs to keep itself alive (read: your brain thinking, your heart beating, your lungs breathing). It accounts for a minimum of 50 per cent of your total energy expenditure.

2. Thermic effect of food – this is the energy expended through digesting food. It accounts for roughly ten per cent of your total energy expenditure.

3. Energy used for movement – this is the energy used to move your body around. It includes all of your incidental movement throughout the day (i.e. walking to the shops, housework, taking a shower), but also any planned exercise. Your lifestyle and daily habits dictate how much energy you expend in this department.

Can you eat to boost your metabolism?

It’s true that some foods can increase your metabolism. The catch, however, is that the increase is marginal and for only a short period of time. If your goal is to lose weight, therefore, you wouldn’t have much success if you only focused on a few specific foods that are claimed to rev your metabolic engine…

Something else that might surprise you in terms of nutrition is that if you are trying to lose weight, you need to consume a minimum number of calories in order to keep your metabolism firing. Contrary to popular belief, weight loss is not about cutting out as many calories as you can, but rather, reducing your intake slightly in order to create a small energy deficit. If you go too far, as many crash diets do, you could actually slow down your metabolism, which is not ideal. To give you a ballpark figure, the average energy intake for adults is 8700 kilojoules (2080 calories). For weight loss, the blanket recommendation is 6300 kilojoules (1500 calories). Anything less than this and you could be doing more harm than good.

On the plus side, it is still certainly possible to boost your metabolism, but via a mechanism you mightn’t have considered yet: exercise. As I’ve already touched on, the amount of energy you burn each day is greatly influenced by how much you move your body… so, if you’re a couch potato, you need to get moving. The rewards of this are two-fold: movement helps to burn calories, but it also helps to build muscle, which in itself will speed up your basal metabolic rate because it takes more energy to maintain lean muscle mass than it does fat mass. Time to hit the gym, I think…

Melissa Meier is a Sydney-based accredited practising dietitian. You can connect with her on Instagram @honest_nutrition.