The ultimate plan to lose weight.
Why don't people like spicy food when they are very young, but they like spicy food when they grow up? Why do we still have a strong desire to pick up and eat a certain food even when we are full? This is the appetite at work. Scientists’ research has revealed why people have a strong appetite for certain foods and proposed ways to train our brains to resist this appetite. This article is translated from Medium’s original article titled "The Neuroscience of Cravings", and I hope to inspire you.
In the Peter Hall laboratory, as a research object, you can eat as much chocolate and potato chips as you want. Does it sound good? But when you gorge on these things, you must wear a helmet device on your head, which can disrupt some signals in the brain with a strong magnetic field energy.
The "Transcranial Magnetic Stimulation Technology" (TMS) helmet is safe, and its effect is only temporary. When the helmet is turned on, it changes the electrical signals in the area of the brain responsible for self-control, thereby halving the wearer’s urge to eat two pounds of chocolate.
All this is to promote the progress of appetite science. Dr. Hall is a Ph.D. in psychology from the University of Waterloo in Ontario, Canada. He is studying what makes people prone to appetite. His equipment is just one of the tools that scientists use to analyze complex psychological, physical and environmental factors. These factors may also combine to give people the urge to eat a certain food quickly.
The discoveries of scientists who study desire often disappoint us. First of all, research has confirmed that people tend to have appetite for foods that are harmful to health. On the other hand, scientists realize that snack businesses have fully mastered the marketing methods of products that stimulate people’s appetite while making these foods within reach. So we have almost no chance to resist them.
But there is also some good news in the research, which reveals some counterintuitive and effective strategies that can fight desire to drive brain attraction. Susan Roberts, professor of nutrition and psychiatry at Tufts University in Massachusetts, said: “When it comes to what we desire, the environment and culture will both work, but we can learn to regain control.”
It is important to distinguish between appetite and ordinary or "physiological" hunger. The latter is a feeling, you need to eat almost all the food that is delicious and provides calories. It is largely caused by some low body energy conditions, such as low blood sugar, fasting, or a slight expected increase in insulin levels. One reason
is so difficult to resist appetite is that they control these hunger signaling mechanisms. Roberts said: "If you walk into a doughnut shop for coffee after breakfast and see that they are making doughnuts, your blood sugar will drop and your insulin will rise slightly. Because of your stomach. Suddenly relax and expand, and even feel an empty stomach.”
Why do we have an appetite for certain foods? The most classic view is that appetite is often related to malnutrition, which is a kind of "physical wisdom" that encourages us to eat what we need most. But now there is a lot of evidence that this so-called concept of food tonic desire is mostly fictional, based only on wishful thinking and some untenable research in the past. Those famous studies on rats and even children, when faced with junk food and healthy food, will they eventually lead themselves to choose a balanced diet? This view was overturned by more detailed research a long time ago. Dr. Kent Berridge, a neuroscientist at the University of Michigan, said: “If you are severely deficient in vitamins or other nutrients, you may get sick and lose your appetite for what you have been eating, which may lead you to try other foods. . But you will not have an appetite for things that lack nutrients.”
Pregnant women eat some strange foods to meet some of their changing body needs. This is a sign of the longest desire for food, but it is also Can't stand scrutiny. Beric said, pregnantHormonal fluctuations during pregnancy may produce some special preferences, but this has nothing to do with health. There is nothing in kimchi that can satisfy nutritional needs. He pointed out that there are several types of malnutrition that may actually be related to appetite. The evidence is more diverse, including lack of salt due to excessive sweating, and possibly a lack of calcium and iron.
Vegetables, whole grains, most fruits and lean protein can be taken off people’s appetite list. Of course, you can like these healthy foods, or even love them and actively taste them. But generally speaking, people's desire for them will not reach an irresistible level. Sherry Pagoto, PhD in Behavioral Psychology at the University of Connecticut, said: “I have never seen anyone have a strong appetite for vegetables.”
Almost all studies Scientists who have experienced appetite have come to the same conclusion: What people crave is food that contains a relatively large number of calories in each bite. This is due to 500 million years of animal evolution and ultimately human evolution, of which about 99.9999% of the evolution is characterized by the constant threat of starvation. In this case, evolution tends to devour food first, and then has the opportunity to swallow the precious calories of the day within 30 seconds, and then think about asking questions, which makes sense. Hunger has nothing to do with this picture-extra high-energy food can be stored as body fat to prepare for the inevitable days of starvation.
In the 20th century, the high-energy appetite that once saved lives has become more likely to harm health. Paben said: "In the absence of food, desire is a good thing given to us by evolution. Now, in this special period of sufficient food, this is not a good thing. This is why most people are overweight."
A study published by the National Institutes of Health in May this year found an interesting way to test the idea that calorie density plays a decisive role in eating impulse. Studies have found that compared with people with low-calorie foods (such as fruits and lean protein), people who eat high-calorie foods (that is, junk foods rich in fat and sugar) will continue to consume more calories. This is true, even if the two groups of people initially eat the same number of calories, including protein, carbohydrates and fat, and they can leave some food at will, or eat more. Think of it this way: An apple and two bites of chocolate brownie sundaes contain the same number of calories, but most people will not continue to eat apples, and few people will not continue to eat sundaes.
Although the connection between appetite and high-calorie food is common, it does not mean that people crave the same food and density. And this is the source of human beings' vulnerability to manipulation by the food industry, and the source of potential freedom for humans to get rid of the desire for harmful health.
A large part of appetite comes from heredity, because the basic preference for high-calorie foods spans generations, regions and cultures. However, the fine-tuning of these appetites is mainly started at an early age, usually related to specific foods enjoyed in childhood. A study of children in Mexico found that when children are very young, they have little interest in spicy food. Until about 5 years old, they will suddenly start to like spicy food like their parents and brothers and sisters. These preferences eventually evolved into a lifelong desire for spicy, high-calorie dishes cooked in a specific way. Roberts said that even in different cultural backgrounds, people's preferences will vary from person to person, and in different situations, people's preferences will also change over time.
Although appetite is changed, the biological mechanism that produces this desire, especially the neural mechanism, and various environmental factors that trigger craving are quite common. "Hormones and other chemicals penetrate from the intestines and liver to generate signals that move the vagus nerve up into the hypothalamus of the brain. The hypothalamus accelerates the release of dopamine, which drives strong desires and rewards," Berridge said . The resulting strong urge to eat any specific food stimulates appetite, which is related to the process of leptin control in the brain. Leptin is a hormone that is released after meals to produce satiety. Imagine your belly might be turkeyIt was bulging with other food, but the pecan pie was placed on the table. At this time, leptin whispered "no", but dopamine shouted "eat".
Although appetite has been programmed into the brain, most of them are just waiting. What excites them is some kind of input from the senses, usually sight or smell. Experts say snack marketers have learned to use this trigger to induce people to buy the craving, high-calorie-density foods they produce.
Spence of Oxford University conducted extensive research on this manipulation in the food industry. He said that the pictures on the food packaging usually show that the serving size is three times the recommended serving size on the nutrition label. Shopping malls set up cafes and bakeries near the stairs to ensure that the attractive smell is emitted throughout the mall. Display high-calorie food pictures on Instagram and advertisements from the perspective of diners. Spencer said: "There is nothing that activates the brain more than the sight and smell of food. When you stare at it, you imagine you put it in your mouth and chew, and imagine how delicious it is."
People are also constantly bombarded by junk food: It seems that there are many McDonald's (McDonald&x27;s), Starbucks (Starbucks) or Dunkin&x27; Donuts in every corner. Hall said: "Our environment provides us with enough high-calorie foods, but low-calorie options are hard to find."
However, researchers have also found that some triggers are avoided or avoided. Techniques to suppress dopamine secretion, such as distraction. Roberts said that there is a very successful method, that is, when you want to eat, pat your forehead and count down from 100. She explained that "appetites often occur in short-term memory. You can drive them out by focusing on a task, or you can walk around the block."
Nutritionist John at Louisiana State University Dr. John Apolzan said that researchers have found that resisting the desire-driven urge to eat junk food has a real and completely unexpected benefit: if you can get your appetite in just a few weeks Remove it from your diet and this desire will begin to decrease. Apolzan said: "Early research showed that when you resist them, your desires will soar, but now it is clear that this is not the case. They decrease because desire is a product of habit, and the more often you succumb They become stronger and more fixed according to your desires. Changing your habits seems to reverse this process.”
Paben suggests to change your environment. You can’t get rid of the cinnamon rolls near the workplace, but you can change your commute route so that you are no longer attracted to them. Paben said: "You have to find a hundred clues that trigger this desire. Not only the food itself, but also other things related to food. If you eat ice cream on the sofa every night, then as long as you As soon as you sit on the sofa, or when you see the bowl you usually eat ice cream, you will want to eat ice cream." To make it easier to identify these hundreds of triggers, Paben and her colleagues developed an app program. Just press the "oops" button when you indulge this unhealthy desire, and record what happens when you surrender to this desire. At the end of the week, the app will provide a report stating what time, place, object or action of the day might trigger your appetite.
Paben said that after she found that people are controlled by unhealthy appetites, just use her app and click the "opps" button. Even if they didn't use the results to change their environment, they would report healthier ones later Some people even lose weight. She said: "We didn't expect to use this button to intervene independently, but now we want to know if this is enough."
Some recent studies have shown that with appropriate stimulation, people may be able to more directly Protect their brains from appetite. Hall is in charge of the TMS experiment, and he said he is studying the device as part of obesity treatment. In the laboratory, he used TMS to temporarily damage the dorsolateral prefrontal cortex (the part of the brain that can resist craving triggers).At that time, a picture of junk food was left in the subject’s field of vision, which eventually caused people to eat more chocolate and fries. But he also found that while showing healthy food pictures, damage to this area can reduce the urge to overeating, which may help lose weight. He said: "We think that if combined with guidance, this may be a good choice for gastric bypass surgery."
Transcranial Magnetic Stimulation (TMS) machine costs 70,000 US dollars and requires well-trained Technicians and clinicians operate, so it is basically impossible to launch a home version at present. Researchers at the University of Exeter in the United Kingdom have developed a gamified application, which is a simpler new way to strengthen the brain against appetite. Users can quickly and repeatedly distinguish between pictures of foods that are unhealthy for themselves and pictures of foods that are considered healthier alternatives to score points in the game. The researchers admit that they don't quite understand why this helps reduce appetite, but the research does confirm this. In real life, when faced with more junk and healthier food choices, linking a simple decision-making process with high scores may help the brain make better decisions.
There may be more applications and other methods to suppress appetite in the future. Can they change people's appetite for vegetables and other healthy foods? Researchers say this seems unlikely to happen yet. But in reducing the appetite for unhealthy foods, we have taken a big step in the right direction.