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Demystifying Metabolism - Part I

Maybe it isn't what we think it is. Strictly speaking, our metabolism is the sum of every chemical reaction in every one of our cells - the total energy we burn each day.

Though, when thinking about the ideal body composition or weight loss, our metabolism can be broken down into several key components.

The most significant of these, which guzzles up around 60 per cent of our daily calories, is basal metabolism where our Basal Metabolic Rate (BMR) is the number of calories our body using on a minute-by-minute, hour-by-hour basis when at rest, simply to keep going. Basal metabolism is the energy expenditure of our basic bodily functions - from pumping materials between cells to maintaining our circulation and vital organs as well as keeping us at just the right temperature. Our brain and liver alone account for half of our energy use at rest.

There is an urban myth that we may not have a healthy body composition because we have a slow metabolism though unless we have an underactive thyroid, generally that's not the case. Actually, the heavier we are, the greater our resting metabolic rate is compared with that of a leaner individual - our body demands more calories just to keep going.

Via Bioelectrical Impedance Analysis (BIA) and some simple body measurements it's possible to calculate our personal BMR or resting calorie requirements. I find at Bridgford & Bingham Nutrition for most of us it's between 1,000 and 2,200 calories a day. It's also worth noting that our metabolic rate will decline as we lose weight – we simply have less body to run and maintain.

While our BMR provides valuable insight, it's important to realise that it's just one piece of the puzzle.

Simply our metabolism is composed of three key elements:-

Firstly, we have this resting or basal metabolic rate. Secondly there's the thermic effect of food - the energy required to digest and metabolise what we eat, typically about 10 per cent of our overall energy expenditure. Finally, we have physical activity. This is the component that we can manipulate significantly, by changing how much we move.

In other words, our metabolic health doesn't have to be a battle on one front. Instead, there are several simple, science-backed lines of attack to increase our calorie expenditure.

In the next blog we’ll explore how we can maximise the elements associated with our metabolic rate.

If you would like to know your BMR or are looking to change your Body Composition please come and see me for your Personal Body BIA at Bridgford & Bingham Nutrition.

Happy eating,

Nina Thomas

Registered Nutritionist & Food Scientist

07958 765337

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