Question from Jack: So what exactly is metabolism?

The term metabolism describes all the chemical processes in our body necessary for us to live. When we talk about it in terms of diet and health what we are primarily looking at is how our body uses energy.

A car gets its energy from petrol, and we get ours from food and we measure this energy in units called calories (or joules which is the metric version). The process of digestion breaks food down so its constituent parts, such as vitamins, proteins and energy, can be used.

Our metabolic rate is a measure of how many calories we need for all those processes to take place. Lots of factors affect our metabolic rate such as muscle mass, activity levels, temperature, age and gender. The more muscle we have the higher our metabolic rate as muscle needs more maintenance and therefore more chemical processes than fat. Exercising increases our metabolic rate while we are engaged in it, but it also stays higher for a while following exercise too. Our bodies need to stay at a pretty constant temperature and being in a cold environment will mean our bodies will have to generate a bit of heat. This increases metabolic rate. Men tend to have higher metabolisms than women – likely owing to a higher muscle mass. Ever heard the term middle-aged spread? As we age our metabolism tends to slow down so we need less calories to live on. However not everyone adjusts their eating accordingly and this can lead to weight gain as we get older.