People often refer to as having a slow or a fast metabolism. This categorization has also been used some times to explain why some people may put on weight easier or slower and /or why they can fail losing weight. Is there such a thing as slow metabolism and if so what can someone do in order to lose weight?
This article will look into some basic metabolic principles and how does energy expenditure (calorie burning) work so as to understand better how to lose weight if you have a slow metabolism.
What is the metabolic rate?
In order to understand what ‘slow’ or ‘fast’ metabolism is and how it affects weight gain, we will first explain some basic metabolic principles. Firstly metabolism is the combination of processes that take place in the body in order to function and maintain life. The means in which we take in nutrients and deliver energy as required is called metabolic regulation.
The rate in which the cells break food into energy (or simplified the rate in which we burn calories) is the metabolic rate. So when people usually refer to a ‘slow’ or ‘fast’ metabolism they usually refer to the metabolic rate.
Each person’s metabolic rate depends on genetics, hereditary factors and amount of lean body mass (i.e. body mass minus fat such as in adipose tissue). However, it must be noted that in the general healthy population these differences are very small and metabolic rate on its own will not necessarily lead to measurable weight changes.
How does the metabolic rate work or measured?
The diagram bellow is a simplified way of explaining how the metabolic rate works.
An important thing to understand here is that regulation of energy metabolism and body weight takes place by highly complex systems and is not as simple as ‘slow’ and ‘fast’ metabolism.
What affects metabolic rate?
A second step is to look into which factors can cause substantial changes in the metabolic regulation and affect the metabolic rate and what makes some people to burn calories slower or faster. Some of these can affect directly the metabolic rate and others can affect hormones or organs which are involved in metabolic regulation and result in dysfunctional metabolism.
Some of the factors are summarised in table1 below; for the purposes of this article we will concentrate only at the aspects which can cause the metabolism to slow down.
|Condition / factor||Effects|
|1. Thyroid dysfunction||Hypothyroidism: in simple words is when the thyroid gland does not produce enough thyroid hormones. One of the effects of hypothyroidism is decreased metabolic rate, and changes in the metabolic regulation. Weight gain can be common in hypothyroidism, not only due to the slowing down of the metabolic rate and the hormonal changes but also as a result of other symptoms. Symptoms such as fatigue, depression, and weakness can lead to decreased physical activity and associated bad eating habits.|
|2. Genetic conditions / diseases||There are a number of different conditions and these can range in the way they affect metabolism and weight gain. However, it is beyond the scope of this article to look into each one in details.|
|3. Very low calorie intake||This could include very low calorie diets, fasting for religious or other purposes, anorexia etc. Metabolism slows down to conserve energy and its own stores. Also muscle mass can be lost which would further decrease the metabolic rate.|
|4. Sleep deprivation||Chronic lack of sleep does not directly lower metabolism. It affects production of some hormones which are involved in metabolic and appetite regulation.|
|5. Stress||Stress affects hormone production which indirectly influence metabolic rate. Stress can have a dual effect. For some people it indirectly increases metabolic rate and for some it decreases it.|
|6. Menopause||During menopause a number of hormonal changes take place some of which influence metabolism. Menopause has been associated with low energy expenditure at rest and exercise and increase in central fat deposit and fasting insulin levels.|
|7. Age||Metabolic rate decreases with age. Some scientist will argue that the decrease in the metabolic rate starts as early as 25 years of age. One of the reasons for metabolic rate changes is the decrease of muscle mass with age.|
How to increase your metabolism?
1. Consult a medical professional: In cases where metabolic changes and weight gain are due to medical conditions/disorders or you have any concerns, the best way forward is to consult the appropriate medical professional. It is important to receive the appropriate medical treatment for any medical conditions, as these could have serious implications to health if not treated properly. In addition, for some medical conditions it is important to follow the appropriate and recommended diets.
You could try every trick on the book for metabolism or weight loss but if not appropriate you could actually be harming yourself and worsening a condition.
2. Increase your muscle mass: Probably one of the most important ways of increasing the metabolic rate. With exercise is not just a matter of burning calories while we exercise. The more muscle mass we have in our body the higher the metabolic rate at rest. In the average healthy person what makes the difference in having a ‘lower’ or ‘faster’ metabolism is muscle mass (more specifically what is called lean body mass which is the muscle mass and organs).
Any form of physical activity will increase the rate in which we burn calories so you don’t necessarily have to join the gym, simple things such as going for a walk, taking the kids swimming, or cleaning the house can help.
3. Avoid very low calorie diets: As mentioned above very low calorie diets can decrease the metabolic rate (see table 1). In order to lose weight decreasing the calorie intake may be necessary and metabolic rate may show some decrease in order for the body to adapt. The recommended calorie intake is 1500-2000 kcal per day for women and 2000-2500 kcal for men.
These are just guidelines and calorie intake does depend on individual factors such as levels of physical activity, age and body build. For a sedentary person who consumes 3000 calories a day is safe to aim reducing the calories within the recommended ranges. For a sedentary person whose calorie intake is within the upper recommended limits then a small decrease up to 500 calories should be sufficient and safe.
There are healthy ways of decreasing calories or increasing energy expenditure instead for losing weight without having to resolve into very low calorie diets.
4. Do not skip meals: Delaying having breakfast will actually help in burning more fat as fuel. However, skipping meals does not help your metabolism. Some scientist will argue that the body needs both periods of fasting and periods of feeding. This could help in improving metabolic flexibility which is the ability of the body to adapt easily in utilizing carbohydrates (sugar) and fats as a fuel and transition between them.
In very simple terms the systems becomes more efficient. In other words avoid loads of small meals and snacks (healthy or not) but aim to have all the meals in a day (i.e. breakfast, lunch and dinner).
5. Increase protein intake: Some studies have shown that protein does help in increasing the metabolic rate. However, you do need to include carbohydrates as well as very low carbohydrate intake can have negative effects in thyroid hormone production.
6. Caffeine: Caffeine is considered to increase the metabolic rate and the use of fat as fuel. However, caffeine is a stimulant and can induce a stress response among other negative effects. Therefore, it would not be recommended to have large amount of caffeine especially if you are experiencing other day to day stresses.
7. Sleep well: As mentioned earlier sleep deprivation can affect the body’s metabolic processes. Sleep is important for the body and it does allow it to reset itself. A good night’s sleep can make miracles for your body in every aspect.
8. De-stress: As with sleep, stress can have negative effects, not only for your metabolism. If you are actually one of those people who lose weight when under stress you may be tempted to think that is not a bad thing. Chronic stress can have number of implications to health and could actually result in chronic conditions.
9. Cold: Cold does increase metabolic rate as the body works harder in order to sustain its body temperature. Some people have gone as far to create the ‘cold diets’ in which they recommend to drink iced water and turn the heating off in the winter.