What is metabolism? Metabolism is the rate at which your body burns calories and is mostly controlled by the Thyroid gland.
Basal Metabolism 65%
The BMR or Basal Metabolic Rate is the rate at which the body burns calories at rest.
In other words, even when you are doing nothing your body is burning calories because it needs energy to run your bodies basic bodies systems, like your brain, breathing and so on.
In fact, two thirds or 65% of your calorie burn are due your BMR. This figure is fixed and is something we can’t control. Click on the link to calculate your BMR.
Thermic effect (TEF) 10%
The good news is that 10% of your calorie burn is due to thermic effect or TEF (Thermic Effect of Food). In other words, when you eat, your body has to digest the food – which takes energy. What is of interest, is that because dietary fat is very easy to process by the digestive system it has very little thermic effect. Protein on the other hand, has a greater thermic effect because it’s harder to process.
In addition, its important to note that meal frequency has little or no effect on TEF – so stick to three meals a day rather than snacking!
What does increase TEF slightly: by about 7-8 calories per hour, is aerobic and anaerobic exercise!
Physical Activity 25%
In fact, your physical activity accounts for 25% of you metabolic burn. This is something you do have control over and is the most significant factor.
Other Factors Affecting Basal Metabolism
AGE : As you get older your metabolism slows down (your BMR decreases) by about 1-2 % per decade after the age of 20. This is mainly due to less physical activity and loss of muscle tissue. This effect can be offset by doing anaerobic strength-training exercise to build muscle mass which also burns more calories than fat.
BODY COMPOSITION: More lean muscle tissue means that you will have a higher metabolic rate which means you burn more calories. In general, men have a higher metabolic rate than women so find it easier to lose weight.
DIETING: This is an important one because a drastic crash diet (less than 800 calories) can mean you can lose 25% of muscle tissue severely impacting your metabolism. Therefore, if you reduce your normal calorie intake from a normal 2000 -2500 longer than a week your body will think you are in starvation mode, your BMR will reduce and your weight loss will plateau.
Researcher Gary Foster estimates that a very low calorie diet of fewer than 800 calories a day would reduce the metabolic rate by more than 10 percent.[46]
In fact, eating more calories can increase your BMR!
HEIGHT: Taller people have a higher BMR so unfortunately if you are short then you are at a disadvantage
GROWTH: Young people when they are growing have a higher BMR – lucky them!
PREGNANCY: When you’re pregnant your BMR goes up.
STRESS: When your body is stressed it can cause the BMR to go up.
TEMPERATURE: A common pathological cause for a high BMR is fever, since a rise in body temperature increases the rate of cellular metabolic reactions. It is estimated that for every degree Fahrenheit of rise in body temperature, the BMR increases by 7 percent.
HORMONES : Hypothyroidism low thyroid function equals lower metabolism. Can be more difficult to lose weight.
https://www.everydayhealth.com/hs/healthy-living-with-hypothyroidism/ways-boost-metabolism/
POST MENSTRUAL SYNDROME PMS BMR increases right before a woman’s period.
MENOPAUSE: Post-menopausal women tend to have a lower BMR which maybe accounts for weight gain around waist.
Conclusions
In conclusion then, if you are trying to lose weight understanding the function of metabolism and BMR is critical and physical activity has the greatest effect.
