Fast or slow metabolism: what does it depend on?
Basal metabolic rate, responsible for nearly 70% of daily energy expenditure, is influenced by numerous factors. Let's list the fundamental ones:
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Diet: in fasting conditions the metabolism slows down by up to 20%.
- Feeding time: in the nurse the basal metabolism increases by about 3-6%.
- Physical activity: the metabolic rate remains high even at the end of the physical effort.
- Climate: Summer is the best time to lose weight because, when the mercury rises above 30 ° C, the metabolism increases slightly. Even too cold temperatures have the same effect.
- Body composition: muscle is a much more metabolically active tissue than fat. Each kg of muscle mass gained raises the body's metabolism by approximately 1.5%.
- Body size: the basal metabolic rate, expressed in absolute terms, increases as the body surface increases. For this reason, tall and thin people have a faster metabolism than individuals of the same weight but of shorter stature.
- Age: metabolism is maximum in childhood, remains high until early adulthood and begins to decrease after age 30. Between 60 and 90 it decreases by about 8% per decade.
- Genetca: however, it must be admitted, some people are born with a slow metabolism, others with a faster metabolism;
- Pregnancy: the basal metabolism remains stable in the first trimester, rises by about 8% in the 5th month and from 14 to 22% in the last two months of gestation.
- Hormone levels: many hormones are involved in the regulation of the body's metabolism. The most active in this sense are those produced by the thyroid. An excessive production of these hormones (hyperthyroidism) can even double the basal metabolism, while a deficit (hypothyroidism, goiter) can significantly slow it down. Also the adrenaline, secreted by the medullary part of the adrenal gland in response to important psychophysical stress, slightly raises the "metabolic activity." Growth hormone and testosterone, by increasing protein synthesis, can significantly raise the basal metabolism.
- Sex: thanks to a greater muscle mass, the basal metabolic rate in men is higher, by about 7%, than in women. Castration lowers it by 20-25%.
- Lifestyle: sedentary people have a slower metabolism than active ones; during sleep there is a decrease in the metabolic rate between 6 and 13%.
- Body temperature: in febrile states the basal metabolism increases by about 13% for each degree of temperature above 37 ° C.
Basal metabolism
Minimum quantity of energy necessary for the body to carry out its pure vegetative functions over 24 hours, in conditions of absolute psychic and physical rest, at room temperature (18-24 ° C) and in strict fasting for 12 hours.
The calorie requirement daily depends on three different components:
- the basal metabolic rate (MB OR MBR from: "basal metabolic rate")
- TID: food induced thermogenesis (also called dynamic-specific action of food)
- Physical activity
The percentage contribution of these components is shown in the image on the side.
You can calculate your calorie needs in a few moments by clicking here.
Think you have a slow metabolism?
The most frequent of the excuses: I'm fat because I have a slow metabolism. In reality, if we analyze the above factors point by point, we realize that this statement has little credibility. Excluding hormonal dysfunctions, for the same sex and muscle mass, individual variations in metabolism are in fact limited. This does not mean that fat people generally have a slower metabolism than thin ones. To get out of this situation, you must first realize that slow metabolism is a consequence of being overweight and not the cause.
Every time you submit to a strict diet, your metabolism slows down, making the diet increasingly restrictive, ineffective and difficult to bear. After a short time, the diet will no longer have any effect, leaving the subject in the throes of hunger and despair. A single, inevitable, binge will be enough to blow up all the sacrifices made up to that moment. Little by little the mistakes will increase, the diet will be definitively abandoned and our poor individual will regain all the lost kilos, with lots of interests , because his metabolism has become slower. And so, between a diet of minestrone and one of fruit, passing through cream, herbal teas and diet pills, the nightmare of being overweight will continue to grip our mister X. Is it the fault of the low metabolism? !
A hungry fox saw clusters of grapes "hanging from a pergola, and tried to grab them. But he couldn't." it is who, failing to achieve his intent due to inability, blames the circumstances.
(Aesop, XXXII; Phaedrus, IV, 3.)
Increase a slow metabolism
To help you boost your metabolism we have prepared a long article; we are convinced that if you read it carefully and put the written advice into practice, you can give your slow metabolism an extra gear.
Speed up your metabolism with training
