Metabolism

When people talk about “speeding up their metabolism”, they are usually referring to something known as the basal metabolic rate (BMR). BMR is the minimum energy required by the body to keep it functioning whilst at rest. It essentially dictates the rate that a person burns calories. For example, someone with a low BMR will burn less energy (calories) whilst at rest than someone with a high one. As BMR accounts for around 60-75% of daily calorie expenditure, having a slower rate could have a substantial effect on whether an individual maintains, gains or loses weight. Luckily, BMR is a flexible trait (it can be reversibly adjusted within individuals). As such, manipulating BMR could potentially be a useful tool for healthy weight management, although further research in this area is required.



BMR can be influenced by many factors including your body size, age, gender, genetic predisposition, hormones and what you eat. The amount of exercise you do can also have an effect. BMR is strongly correlated with fat-free mass (FFM). While fat burns very little energy, muscle is an active tissue that uses up energy even whilst at rest. In light of this, one of the most effective ways to increase your BMR is by engaging in exercise that increases your FFM. Resistance, strength and weight training is the most effective at building muscle and increasing BMR. A further tip for increasing BMR is to turn off the central heating every now and again and expose ourselves to drops in temperature, as our bodies naturally burn more energy in colder climates in order to keep us warm. Staying well-hydrated is also recommended as evidence suggests that drinking water may temporarily speed-up resting metabolism by 10-30%. Certain foods and drinks also appear to have an effect. For example, studies suggest that eating protein-rich and spicy foods and drinking green tea may have a beneficial effect on metabolism.

 

Interestingly, research indicates that the composition of bacteria we have in our gut (the microbiome) may also play a role in energy metabolism. An imbalance in bacteria is often observed in overweight individuals and those who make poor food choices. Research suggests that the obese microbiome may harvest more energy from the diet, influence food cravings, manipulate taste receptors and increase total body fat. Supporting a healthy microbiome by eating a wide variety of fibre-rich fruit and vegetables to provide a food source for beneficial species in the gut is therefore recommended for weight management.