Why do we get fat

Chapter 17 The Laws of Obesity (2)
Well, but it's these same "20 calories a day" precision requirements that make it easy for the control system to get out of hand, and any misalignment can end up causing major turmoil in our fat cells and making us fat.If an unfortunate combination of genetic and environmental factors caused the control system that regulates fat to go awry, causing as little as 1% of the calories that should be used as fuel in the body to be stored in our fat cells by mistake, then we You are bound to gain weight.

Some people could end up very fat if only a tiny bit more of those wrongly converted calories into fat.A little mistake can really lead to big consequences.

The third law of obesity

Anything that makes us fat also tempts us to eat too much.

This is the most important lesson of Wade's experiments with mice.Perhaps this law is somewhat counterintuitive, but it is true for every species, every human being who has gained a few extra kilograms of fat.It's arguably the lesson we, and health professionals, have to learn in order to figure out why we gain weight and what we can do about it.

Any object that increases in mass (weight), for whatever reason, must take in more energy than it expends.Well, if fat regulation fails and we get fat and heavy again, it is safe to assume that we eat more calories (growth in appetite) and expend less energy than if regulation is normal.

Growing children can help us understand the cause-and-effect relationship between obesity and eating more.My eldest son weighed about 15kg when he was less than two years old, and after three years he grew 20cm and weighed about 23kg.

In three years he had gained 8kg and he was definitely taking in more calories than he expended.He ate "too much".Those extra calories are used to create the tissue and structure necessary for a larger physique.Yes, including more fat too.However, he does not grow because he eats too much; he eats more because he needs to grow.

Like every small child, my son's growth is largely regulated by the action of growth hormone.He sometimes grows faster as he gets older, along with a voracious appetite and maybe a little laziness.

Big appetites and laziness are driven by growth, but you can't say that growth makes us gluttonous and lazy.The child's body needs "excess" calories to meet the needs of growth. To grow taller, it is necessary to increase appetite and reduce energy consumption to obtain excess calories.After puberty, he still eats more calories than he burns, but he loses body fat and gains muscle—also driven by hormonal changes in the body.

Growth is the cause, eating more is the result.This is also true for our fat tissue.We never thought it possible that children would grow taller because they ate too much, moved too little, or exercised too much and stunted their growth—so why would these be reasonable reasons for getting fat? explain? More than 80 years ago, German physician Gustav von Bergmann wrote: "The body can always find what it needs to grow and what it needs to turn into fat. The body can always be in a good range of regulation. Let our bodies perform at a high level."

Growth determines appetite and even energy consumption. We don't gain weight because we eat more, we eat more when we gain weight.

While this is so counter-intuitive, it's critical to properly understanding weight loss, so I need to go back to the animal example.African elephants are the largest land animals in the world. Male elephants usually weigh more than 4.5 tons, but there are almost no obese elephants.The blue whale is the largest animal in the world, its weight can reach 136 tons, most of them are very fat.African elephants eat hundreds of kilograms of food a day, and blue whales eat tons of food.These are indeed impressive amounts of food, but neither animal grew to such a large size by eating a lot.It's because of their large size that they eat so much.Whether you have a lot of body fat or not, your body size determines how much you eat.

The young of these species also eat relatively a lot.They eat this because they are born relatively large, and their genes make it easier for them to grow into elephants weighing several thousand kilograms or blue whales weighing hundreds of tons.Both growth and body size promote appetite.This is true whether the animals use the calories to store fat or to build muscle mass or enrich other tissues or organs.The same causality applies here whether they have a lot of fat or not.

Now let's consider what researchers call obese taxidermy—animals that have been artificially fattened in the laboratory rather than becoming obese naturally, such as Wade's lab mice.Over the past 80 years, researchers have learned to fatten mice large and small through feeding, surgery (eg, ovariectomy), manipulation of diets, and numerous genetic manipulations.Animals that were handled roughly did get fat, and not just the normal fat of blue whales and ground squirrels, but they were also more prone to various metabolic disorders, including diabetes.The same goes for us humans when we get fat.

However, it doesn't matter what kind of experimental technique makes the animals fat, whether or not they eat more calories than their lean counterparts, they will gain a lot of weight and develop other metabolic diseases, just like Wade's experimental mice .

They gain weight not because they overeat, but because of surgery, feeding methods, genetic manipulation, and even dietary changes that interfere with the self-regulation of their own fat tissue.The mice started storing calories as fat, and their bodies then had to compensate.Then, if possible, they eat more; if not, they expend less energy.From the guinea pigs, they often do both.

Take, for example, the method used by scientists from the 20s to the 30s to make lab mice fat.The technique involves inserting a needle into a brain region called the hypothalamus, which controls hormone production throughout the body.After the operation, some mice became fat because they were gluttonous, some became fat because they were lazy, and some became fat because they were both greedy and immobile.The Northwestern University lab of neuroanatomist Stephen Ranson, who pioneered the approach, is the first to show the obvious through experiments that surgically destroying brain regions directly affects fat gain in these mice.After surgery, the animal's adipose tissue is overloaded with calories to add more fat, which leaves insufficient fuel for the rest of the body and forces the body to respond by either increasing food intake, reducing energy expenditure, or both do all.Ranson calls this "stealth hemicellular deficiency."

The only way to prevent these animals from becoming obese was to starve them, subjecting them to "severe and persistent" food restriction.If these animals eat even "moderate" amounts of food, they still end up getting fat.In other words, what makes them fat is not eating more, but eating.After brain surgery, the rhythm of body fat regulation in mice was changed, which had a huge impact.However, it has no effect on whether the appetite is strong or not.

The same conclusion applies to animals that are fed fat, for whom obesity is written in their genes. In the 20s, Gene Mayer studied the kinship of obese mice in his Harvard lab.According to his report, if he starved fat mice to a certain extent, he could make them weigh less than lean mice, but "they still had more fat than normal mice, while their muscles disappeared."Once again, eating too much isn't a problem.As Meier writes, these mice "continued to produce body fat even when food was least likely to be available, even when they were semi-starved."

There's also the Zoker rat, which researchers have been studying since the 20s, and they're still a beloved obese specimen.Zucker-mouse always looks fat and well-proportioned.

Like the mice in Meier's lab, the mice were genetically predisposed to gain weight.Assuming a Zocker rat is put on a calorie-restricted diet from the time it is weaned, they will end up not being leaner than their mates who can eat and drink as much as they want, but rather fatter.They may weigh slightly less, but have the same amount of body fat, or even more.They want to binge eat (of course they want to), but can't.Under these harsh conditions, Zoker rats still became even fatter than those that never dieted.On the other hand, their muscles and organs, including their brains and kidneys, developed smaller than they would have been without the diet.Just as Meier's mice lost their muscles when they were starving, the muscles and organs of these semi-starved zork mice were significantly smaller than those of their fat counterparts who could eat and drink freely. Publishing this observation in 1981, the researchers wrote: "Faced with calorie restriction, certain organs and even systems are compromised in obese mice in order to develop obese tissue in their bodies."

Let's think about this for a moment.If a fat pup is put on a diet from weaning, it will certainly not eat as much as a lean mouse.In this case, it can no longer eat to its heart's content. In order to cope with this situation, its organs and muscles will "compromise" to satisfy the genetic drive of obesity.It doesn't just use the energy consumed by daily activities to increase fat, but uses the raw materials and energy normally used to develop muscles, organs and even the brain to produce fat.

According to the literature, when these fat mice were starved to death (fortunately, there are not many researchers doing this kind of experiment), a common result is that most of their fat tissue is still intact.In fact, they died with more body fat than their free-wheeling companions.Humans, like animals, consume muscle for fuel when they are starving, eventually even including heart muscle.To maintain their fat, these obese animals are willing to compromise - sacrificing their organs, even their hearts and their lives.

The message from 80 years of research on obese animals is simple, clear, and worth reiterating: Obesity is not due to gluttony and laziness, and simply altering the regulatory properties of adipose tissue can make lean animals fat.

The amount of body fat in an obese animal is determined by the balance of all the forces acting on the adipose tissue to draw in or out of fat.Whatever is done to animals to make them fat, whether surgical or genetically manipulated, the end result is to alter the balance of regulatory capacity, so that the animals increase their fat stores.Now, the concept of "eating too much" is meaningless, because other normal amounts of eating are now becoming "too much".The fat tissue in these animals did not respond to how much the animals ate, only to the forces that caused them to accumulate fat.Since building body fat depends on energy and nutrients, animals will eat more whenever possible.If conditions do not allow it—for example, if you want to go on a diet to lose weight—because there is not much energy left to expend, the body may even compromise the brain, muscles, and other organs at this time, giving up energy to accumulate fat.Even when animals are half-starved, they can still find ways to store calories as fat because their adipose tissue is now genetically programmed to do so.

There is no reason to think it is wrong if we say the same is true for humans.This would explain the phenomenon I mentioned earlier that challenges the conventional wisdom about the coexistence of extremely poor overweight mothers with small, stunted children.In fact, both mother and child are half-starved.As expected, the children were emaciated and stunted.Yet the mother's fat tissue has developed its own "agenda" (we'll see how this happens shortly).It accumulates excess fat, even if the mothers themselves, like their children, are given just enough to survive.To compensate, they must reduce the amount of energy they expend.

Before I put aside the laws of obesity and animal studies, I want to ask one more question: What about people who are always thin no matter what?Over the years, researchers have also created what we call "slender taxidermy"—small animals that have been genetically engineered to be slimmer than their average counterparts.Even when the researchers forced them to eat more calories—for example, by injecting nutrients directly into their guts with a hose, feeding the calories directly—the animals remained lean.In this case, the animal must increase consumption to burn off these extra calories.

Just as animal studies have shown us that gluttony and laziness are side effects of the drive to accumulate body fat, it also demonstrates that neither eating moderately nor being active can be relied upon to judge people's moral character.In fact, you have to have extra energy to move.

In the same way, the reason why professional marathon runners are slim is not that they train hard sincerely, so they burn a lot of calories, but their body circulation drives them to distribute energy to muscles to burn calories, intuitively The effect is to stay lean.Likewise, the greyhound (a very lean dog with muscular legs, used for racing) is more active than the Basset Hound, not because of an active moral quality in their consciousness, but because of its physical The circulatory system divides the fuel it gets to muscle tissue rather than fat tissue.

"We're virtuous so we're thin, or we're fat." That might be more convincing and reflective, but the evidence suggests otherwise.Conduct has nothing to do with our height, any more than it has to do with our weight.We grow taller because of hormones and enzymes, we gain weight, why not?Growth is the cause, increased appetite and reduced energy expenditure (so-called gluttony and laziness) are the effects.This is the case when we gain weight.

To be clear, don't hold your head up because of hearing words like "you eat too much", "gluttony" and "lazy". The reason for weight loss failure is not a quality problem.We get fat not because we eat more; it is because we get fat that we eat more.

(End of this chapter)