We often hear the word metabolism and people suggesting that their weight gain is due to a slow metabolism.  So what is it, can it slow down, can you speed it up?

Metabolism refers to a complex series of processes in the body that convert food into energy to allow your body to function, to move to breathe, to think, break down old tissue and build new tissue.  Ultimately it’s the amount of energy, or number of calories, you need to keep functioning and stay alive.

One measurement often used that many people will have heard of is BMR or basal metabolic rate.  Some smart weight scales will work this out for you and it is based on your gender, age, height and current weight.  Your BMR is the number of calories you need to just survive.  As an example a 40 year old, 5ft 9in male weighing 12 stone has a BMR of 1721 calories.  If this were a female it would be 1521 calories.  If you increase the subject age to 60 the BMR is 1586 and 1427 for male and female respectively.

Of course you then need to add in other calculations for movement, which would include work, exercise and interestingly even eating which requires energy. This is where we start to see some real differences because of people’s lifestyles.  So for inactive people you would multiply their BMR by a physical activity factor of 1.4.  If you do that with the examples I gave above you can see where the oft-quoted 2000 calories per day for a female and 2500 calories for a male come from.  However that factor increases as people become more active so a moderately active female can factor up by 1.6, for a male by 1.7 and for very active people the factor goes to 1.8 for women and 1.9 for men.  This means using the above example of the 40 year old, if they were training hard 5 or 6 times a week the female would need about 2700 calories per day to provide enough energy and the male would need almost 3300 calories.

So metabolism is the key factor in controlling weight and where necessary increasing or decreasing weight.  Important to remember, the equation is simple, where calories eaten is the same as calories turned into energy then weight stays constant, increase the input with the same output you will gain weight, increase the output so it is higher than the input and you will lose weight.  So are there ways to change your metabolism?  I think from the above calculations you can see that activity is key; so back to the point I made in my last post it’s about movement.  But there are some ways of making this even more effective.  

But first let’s start by looking at ways your body will slow down your metabolism and it is a natural function that we all experience daily, fasting.  When you sleep the body shuts down many functions but it still needs to use energy to keep vital functions going, so you do burn calories overnight.  Because you aren’t eating and providing more energy sources to be absorbed, the energy in your circulatory system, blood sugar, starts to fall and this will be maintained by a store of sugar in the liver.  However this store generally runs down while you sleep so your energy levels will be lower when you wake.  Without replacing some of that energy i.e. by eating, the body will lower the body metabolism to try to maintain vital functions for longer.  My point here is to see how important breakfast is to just revitalise the energy systems.  I am sure we all recognise that sluggish feeling until you have eaten and probably seen it with our children whose cognitive ability at school will be lowered.

If you can see how easy missing breakfast is to decreasing our metabolism I shouldn’t need to point out how dieting has the same effect, however I will point it out.  If you deliberately fast, or diet, your body will react to it immediately and turn down it’s calorie burning ability.

So how can you increase your metabolism?

Eat breakfast

Eat according to your activities.  What do I mean by this?  If you know you are going to exercise heavily you need to make sure you have the energy to do this.  If you exercise hungry you will not be able to exercise as hard.  On days when you are less active then eat less.

Eat protein.  I say this for a number of reasons.  Protein is used primarily for the repair and building of the body’s tissues which includes muscle.  If you are exercising heavily then you do need to provide more protein for the extra repair work after exercise.  Protein is quite filling so helps quell hunger.  To breakdown food in the digestive system requires energy and protein is much harder to breakdown than carbohydrates and fats so burns off more calories.  You don’t need to overdo your protein intake and there are ways of working out how much you need when you are more active.

Don’t skip meals.  Eating regularly keeps energy levels more even.

Do cardio.  Apart from the cardiovascular benefits few things rev up metabolism more than getting the major muscle groups moving.  

Lift weights.  This doesn’t mean you have to be bench-pressing 100plus kg in your program, unless you want to of course.  I’m talking about strength training so this can often be done with bodyweight or small weights.  It is the movement of muscle that burns energy quickly so the maintenance of a good muscle mass helps with your metabolism.

High intensity training.  Although this should not be your sole method of training, it is more likely to lead to injury and overtraining, you should consider incorporating this into your weekly program.  It could be a circuit, it could be Spin, it could be a 2km sprint on the rowing machine or interval training when running.  The advantage it has over steady state training is it continues burning calories for sometime after you have finished exercising while the body comes back to its stable state.

I hope this has helped you to understand the basics of what metabolism is and how we can easily have an effect on it with our diet and exercise.

If you want to know more about nutrition and want an exercise program that includes the most effective ways of increasing your fitness and metabolism, then think about personal training.

Next blog entry I will talk some more about the 3 macronutrients we all eat, carbohydrates, proteins and fats.  What we use them for in our bodies, how they provide energy generally and for fitness training.

John Ford
Personal Trainer
07584 087098