Metabolic Facts To Help You Manage Your Body

2024 Author: Malcolm Clapton | [email protected]. Last modified: 2023-12-17 03:44

When it comes to metabolism, it usually comes down to manipulating it with pills or green tea to speed it up. But metabolism is a much more complex process. We've compiled scientific facts to help you better understand metabolism and use that knowledge to lose or gain weight.

1. Metabolism occurs in every cell of your body

Many people talk about metabolism as a muscle or organ that they can control in some way. In reality, metabolism is a series of chemical processes that convert calories from food into energy to sustain life, and this happens in every cell of your body.

Your resting metabolic rate, or basal metabolic rate, is determined by how many calories your body burns while you are doing nothing.

The human body needs energy at rest to maintain its own life - for breathing, circulation and digestion of food. Different types of tissue have different needs and require different amounts of calories to function. The vital organs - the brain, liver, kidneys and heart - account for about half of the energy produced. And on adipose tissue, digestive system and muscles - everything else.

2. You burn the most calories at rest

Your body burns calories:

• at rest (basal metabolism) - the energy received is used for the functioning of the body;
• in the process of assimilating food (known thermal effect);
• with physical activity.

most of the calories per day you burn at rest during metabolic processes. Physical activity, in comparison with basal metabolism, accounts for a small part of energy expenditure - from 10 to 30% (if you are not involved in sports professionally or your work does not require heavy physical labor). About 10% of energy is spent on the digestion of food.

On average, basal metabolism accounts for 60 to 80% of total energy expenditure. Of course, this is not all, but in combination with the energy consumption for food processing, it turns out to be almost 100%. Therefore, it is not surprising that exercise leads to statistically significant, but small, changes in weight.

Alexey Kravitz is a neurobiologist at the National Institute of Health

3. The metabolic rate can vary greatly from person to person, and researchers don't understand why

It's true that the metabolic rate of two people of the same height and body size can be very different. While one can eat anything in huge quantities and his weight will not change in any way, the other has to carefully calculate calories so as not to gain extra pounds. But why this happens, no scientist can say for sure: the mechanism of metabolic control is not fully understood.

However, the researchers found indicators that affect metabolic rate: the amount of muscle and fat tissue in the body, age and genetics (although it is also not entirely clear why some families have a higher or lower metabolic rate).

Gender also matters: women of all ages and builds burn fewer calories than men with the same parameters.

It is not possible to easily and accurately measure the metabolic rate. There are special tests available, but they are unlikely to guarantee a perfect result. Accurate measurements require expensive equipment such as metabolic chambers.

You can use an online formula calculator to get a rough estimate of your metabolic rate. This will tell you how many calories you need to consume per day to keep your weight constant.

4. The metabolism slows down with age

This happens gradually and with everyone, even if the ratio of muscle to fat tissue remains the same. When you are 60, you will burn fewer calories at rest than at 20. The researchers note that a gradual slowdown in metabolism begins at the age of 18. But why does the need for energy decrease with age, even if all other indicators remain the same? Scientists cannot answer this question.

5. You cannot significantly speed up your metabolism for weight loss

Everyone is constantly talking about how you can speed up your metabolism in order to lose weight: play sports and build muscle mass, eat certain foods, take supplements. But it's actually very difficult to do.

Certain foods can actually speed up your metabolism, such as coffee, chili peppers, and hot spices. But the change will be so minor and short-lived that it won't have any effect on your waistline.

Building muscle is a more potent option. The more muscle and less fat, the higher the metabolic rate. This is because muscles require more energy at rest than adipose tissue.

If you can gain muscle mass and reduce body fat through exercise, your metabolism will accelerate and you will burn calories faster.

But this is only half the battle. You will have to overcome the natural urge to eat more, which comes with the accelerated metabolism. Many people succumb to the feeling of hunger that comes after hard training, and as a result they build not only muscle, but also fat. In addition, many find it difficult to train necessary to maintain the gained muscle mass.

It is foolish to believe that you can completely control your metabolism. If you are able to influence him, it is on a modest scale. And this will require willpower and perseverance.

6. Diets slow down metabolism

Speed up your metabolism is not easy, but slowing it down is much easier with programs for fast weight loss. Diets have the strongest effect on metabolism, but unfortunately not as much as we would like.

For years, scientists have been researching a phenomenon called metabolic adaptation, or adaptive thermogenesis. When people lose weight, their basal metabolic rate slows down quite significantly. It is clear that the metabolism should slow down a little, since losing weight involves losing muscle mass, the body becomes smaller, it does not require as much energy as it used to. But the researchers found that the metabolic rate slows down to a much greater extent, and this effect is not only associated with changes in body composition.

In the latest study on the topic, the results of which were published in the journal, scientists from the National Institutes of Health examined participants in the reality show The Biggest Loser. By the end of the show, all the participants lost a lot of kilograms, so they were ideal for researching what happens to the body with significant weight loss in a short period of time.

Scientists studied a number of indicators - body weight, fat, metabolism, hormones - at the end of a 30-week competition in 2009 and six years later, in 2015. Although all the participants had lost a lot of weight by the show's finale through exercise and diet, after six years, their volumes have largely recovered. Of the 14 participants in the show, 13 people returned their weight back, while four of the contestants began to weigh even more than before participating in the show.

During the study period, participants' metabolism slowed significantly. Their bodies burned an average of 500 calories less each day than would be expected given their weight. This effect was observed even after six years, despite the fact that most of the participants gradually gained the lost pounds.

Sandra Aamodt, a neuroscientist and author of Why Diets Usually Don't Work, attributes this to the body’s special defensive response to maintain weight in a certain habitual range.

After you gain weight and hold it for an extended period of time, your body gets used to its new size. When weight falls, small changes in hormone levels in the brain slow down the metabolism. At the same time, the feeling of hunger increases and the feeling of satiety from food decreases - it seems that the body is trying with all its might to return back to its usual weight.

In a study of the participants in the show The Biggest Loser, scientists found that each of them had a decrease in the concentration of the hormone leptin. Leptin is one of the main hormones that regulate hunger in the body. By the end of The Biggest Loser, the contestants had almost completely depleted their leptin stores and were constantly feeling hungry. In six years, their leptin stores recovered, but only to 60% of their original pre-show levels.

Most people have no idea how dramatic metabolic changes can be after weight loss. With weight gain and weight loss, the body does not behave the same way. He fights much harder to keep his weight off than to stop the gain.

But weight loss does not always lead to a slowdown in metabolism. For example, surgery to change weight does not change leptin levels, nor does metabolic rate.

Moreover, the research with the participants of The Biggest Loser is rather non-standard, so it is not a fact that most other people will experience a similar effect. Indeed, the study involved only 14 people who lost weight solely through fast diets and exercise. This effect of slowing down the metabolism is not observed with gradual weight loss.

7. Scientists cannot fully explain why metabolism slows down

There are several theories on this score. One of the most reliable is explained by the course of evolution. Over the millennia, humans have evolved in environments where they had to cope with frequent periods of malnutrition. Therefore, it can be assumed that many genes have been preserved in the DNA that contribute to the conversion of excess calories into fat. This ability helped humans survive in times of food scarcity and reproduce.

Continuing the thought, we can say that the inability to lose weight today is due to the body's defensive reaction, even though the lack of food in our society has become a rarity.

But not all scientists agree with this theory of the thrifty gene.

If thrifty genes provided a strong selective advantage to survive hunger (famine periods have been frequent throughout history), thrifty genes would spread and become entrenched throughout the population. This means that today we must all have thrifty genes, and then modern society would consist exclusively of overweight people. But even in the societies that are most prone to obesity, such as the United States, there is always a certain number of people, on average about 20% of the population, who remain invariably thin. And if hunger is a prerequisite for the proliferation of thrifty genes, it’s logical to ask how it came about that so many people managed to avoid their inheritance.

John Speakman epigeneticist

Scientists are also trying to better understand metabolic syndrome, which is a complex of metabolic disorders that include high blood pressure and blood sugar levels, a large waist, and abnormal cholesterol and triglyceride levels. When people have these health problems, they are more at risk for chronic diseases, including cardiovascular disease and diabetes. But again, it is unclear how metabolic syndrome works and why some people are more susceptible to it than others.

8. Slow metabolism doesn't mean you can't lose weight

Weight loss is possible with a slow metabolism. On average, 15% of people with a slow metabolism at the Mayo Clinic lose up to 10% of their own weight and retain a new one.

Anyone looking to lose weight can achieve this goal by changing their lifestyle. It is also important to make adjustments to it that will keep the disease - obesity - under control.

The National Weight Control Registry in the United States investigates the habits and behavior of adults who have lost at least 15 kilograms and were able to maintain that weight for a year. The roster currently has more than 10,000 members who are regularly polled annually on how they manage to maintain a healthy weight.

These people share several common habits:

• they are weighed at least once a week;
• exercise regularly and walk a lot;
• limiting calorie intake, avoiding foods high in fat;
• monitor portion sizes;
• have breakfast every day.

But everyone eats completely different foods, they plan their diet in different ways. Therefore, it is impossible to say for sure which diet is the most effective. The main thing is to keep track of calories.

In addition, all the people who managed to lose weight made major changes in their lifestyle, were more attentive to their diet and did physical exercise. Of course, many would prefer to think that their weight problems are due to a slow metabolism or any other biological disorder, and not because they are lazy and like to eat. Science confirms: if you really want to lose weight and are willing to put in the effort, you will succeed.