The calorie needs of a 50-year-old are not that different from those of a 20-year-old. So why do we get fat? How metabolism changes in the four phases of life and how to stay fit after middle age
true that as adults and as we get older we need to eat less? Certainly yes, but not as much as is generally thought.
Not a variable linked only toet: as the years pass, the metabolism (the ability to consume energy/calories) definitely increases less efficientbut they weigh a lot some other factors which can be modified (in our favor).
How metabolism works
To understand how theage data affects calories necessary every day, we must consider all the other factors that determine a person’s energy needs, i.e how much he should eat (which translates to calories) to keep your body functioning and performing daily tasks.
Maintain vital functions of the organism (breathing, heartbeat, blood circulation, minimum activity of the nervous system, etc.) burns approximately 55-70% of the daily calorie requirement and a function that varies based on age, the person’s size, genetics, sex: yes who loves basal metabolism.
The working metabolism, instead, the sum of the energy spent in movement and for the assimilation of food. The energy spent in physical activity It varies depending on the type, frequency and intensity of training and burns approximately 20-40% of your daily calorie needs. The energy spent on the digestion of meals burns about 10% of your daily calorie needs.
Body structure affects calorie needs
That’s why, to determine how much it is necessary to eat is the key variable, because it depends only on us, physical activitywhich also affects our body structure: Who has developed a lot of muscle mass or, conversely, one overweight person or obese do not have the same energy needs as a person of the same age, sex, height, but different mass – he clarifies Elena Dogliottibiologist, nutritionist and scientific supervisor for the Veronesi Foundation —: energy expenditure, in fact, also depends on the percentage of fat and lean mass present in the individual.
The newborn consumes more
Excluding these variables, we come to the analysis of how theet affects our calorie expenditure.
If we do a weight/calorie ratio, childhood the moment when you need to eat more. Follows theadolescence: In the first phase of life in which the organism is growing, the metabolism works at full speed because there is the need to produce more cells, there are physiological processes that increase the body (even in height), generate hormones and proteins – explains the specialist -. As we get older, the need decreases, then remains stable in adulthood and decreases after the age of 60.
Metabolism: stable from 20 to 60 years
A study conducted at the Duke University of North Carolina (USA) Published on Science
analyzed the course of human life determining 4 phases of metabolism (see the image of the two graphs above,
ed):
– childhood (up to the age of 1 year), when calorie consumption is at its apex;
– the youth (up to about age 20), when the metabolism Slows gradually by about 3% per year;
– L’adult age (up to the age of 60), when the metabolism is maintained stable (also during pregnancy and menopause);
– L’and geriatric (after age 60) when the metabolism decreases slowly by about 0.7 percent per year.
Minor requirement, but very little
Energy needs change over time, true, but not substantially: They are wastes of a few kilocalories – specifies the specialist -: if we remained the same in mass and habits, they would be something like 200 kcal less to eat per day.
Age affects calorie needs because the decrease in physiological muscle mass – says Dogliotti -: we can counteract it a little with physical activity and with an adequate protein intake, but from thirty years of age onwards the organism is more inclined to accumulate fat.
Slight waste
Even the tables of average energy needs in adulthood and geriatrics compiled by SINU (the Italian Society of Human Nutrition) confirm the minimal differences (see graph below, ed):
– a sedentary man 1.80 m tall from 18 to 29 years old needs on average 2,590 calories, 2,480 calories from 30 to 59 years old and 2,190 calories from 60 to 74 years old, with differences of 110 calories and 290 between the various phases.
To give you an idea, an empty brioche has around 200 kcal.
– For them sedentary women (height 1.70 m)
the similar discussion: 2,100 calories between 18 and 29 years, 1,990 from 30 to 59 years and 1,800 calories from 60 to 74 years and the deviations are 110 and 190.
The metabolism slows down, then, but not so significantly there are no jumps corresponding downhill at 40 years old (the so-called middle age) or at menopause
.
Why do we tend to gain weight as adults?
So why do we tend to gain weight as adults? People on average gain more than a pound and a half on the scales per year after about age 40. Age matters – we anticipated it – when it comes to body composition: You don’t have to eat little, but your consumption changes because you move less and probably have less muscles – says the expert -. Less muscle means more fat And the fat body consumes fewer calories and slows down the metabolism. 200 extra calories per day have no impact, but if they are 200 for 365 days a surplus that will accumulate. imperceptible at first, then perhaps translates into 5 kg more on the scale after 10 years.
The good news? The metabolism of a 50 year old is not that different from that of a 20 year oldas long as we remain active and counteract with muscles the tendency to accumulate fat mass.
October 22, 2023 (modified October 22, 2023 | 08:11)
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