Metabolism - is it under your control?

When I meet with a new client for the first time to discuss their weight loss goal and our strategy to achieve it the word 'metabolism' is often mentioned. A 'slow metabolism' is blamed in a lot of cases for previous failed weight loss attempts and slow weight loss results. Metabolism in this context is referring to basal metabolic rate (BMR) or its close relative resting metabolic rate (RMR) which is the rate that energy is 'burnt' by the body at rest. Greater the BMR, the more energy is burnt by the body in a resting state, lower the BMR, the less energy is burnt by the body in a resting state. By increasing BMR, the amount of energy being burnt continually across the day is increased. Since weight loss requires a greater energy 'out' than 'in', BMR is of particular significance for all weight loss programs.


BMR represents 60-75% of total energy expenditure for most people. This is significant when compared to physical activity which represents 15-30%. When you consider this comparison it is obvious how important your BMR is for achieving weight loss results. The individual differences in each persons BMR therefore offers an explanation as to why some people gain weight more easily than others when consuming the same amount and type of foods.

Despite being influenced by genetics your BMR is to a large extent under your control. Diet and physical activity are both under our control and both strongly influence BMR. I will address these points individually below.

Diet can strongly influence your BMR. Eating regular meals across the day, as opposed to fewer larger meals, can help to increase your BMR. Aim for 4-6 meals spread evenly across your day. Eating as soon as possible following waking up can also help to increase your BMR. Your body has the ability to recognise when it is 'starving' and can, as a result, slow BMR in an attempt to preserve energy - this is a survival adaption in response to a reduction in available energy. This may be experienced as a result of long breaks between meals (such as over night) or as a result of low energy intake (such as that imposed by fad weight loss diets). It has been estimated that a very low energy diet of 800 calories or less can decrease the BMR by greater than 10%. This is why extreme dieting is not the most effective method for weight loss. Aiming for a diet of no less than 1200 calories can help to avoid reductions in BMR. Drinking adequate water during the day, 2L or 8 glasses, reducing alcohol intake and consuming high fibre, nutritious and low glycaemic index (GI) foods may contribute to increasing BMR. Some specific foods or components of foods have been shown to have a thermogenic effect on the body increasing BMR, such as caffeine. Evidence suggests that the thermogenic effects brought about by consuming certain foods are both minimal and short term and therefore should not be the dietary focus when looking to increase BMR.

Physical activity can also increase your BMR. You may find it surprising to hear that resistance training is in fact the most effective type of physical activity for increasing your BMR. That's right, lift weights - lose weight! Unlike fat mass, muscle mass is metabolically active tissue which means it is constantly requiring the release of energy and as a result is constantly burning energy across the day. The greater your muscle mass, the greater your BMR. One of the biggest mistakes people make is leaving resistance training out of there exercise program when they are trying to lose weight. Increasing your BMR with resistance training also means that weight is more easily kept off once it is lost. Cardiovascular physical activity while important for direct calorie burning at the time of exercise and during the recovery time that follows, has not clearly been shown to provide the same long term increases in BMR. Your metabolism increases during cardiovascular exercise in response to the increased energy demands of the activity and your metabolism also remains elevated following cardiovascular exercise as it recovers and returns to resting. A combination of regular resistance and cardiovascular training is recommended for maximising your BMR.

There are other factors that influence BMR that are in some cases completely out of your control such as age, gender, disease, mood and prescription medications. Focus on the factors that can be controlled. Your metabolism is largely under your control, do not use it as an excuse, take control of it and give yourself the best chance to lose and manage your weight.

A quick list of the top 5 points to remember are outlined below:

• Eat regular meals across the day aiming for 4-6 smaller meals
• Eat as soon as you wake up
• Eat high fibre, low glycaeimic index (GI), nutritious foods
• Do not over restrict energy intake
• Participate in regular resistance training