As we all know, obesity has become a global health problem. If this trend continues, obesity will soon surpass smoking and become the largest single cause of premature death in the world, and it will also reduce people's quality of life and increase medical expenses. According to the statistics of the Centers for Disease Control and Prevention (CDC), as Americans become fatter,13 adults are obese, and13 adults are overweight. A study by JAMA shows that obesity causes more than 654.38+600,000 "accidental" deaths every year.
The urgent situation makes us eager to answer the question: Why is it so difficult to remove excess fat? It shouldn't look so difficult. The basic principle of losing weight is simple: as long as the energy intake is less than the energy consumption. However, if it were so easy, obesity would not become a major health problem related to lifestyle in the world.
Obesity is a multifactorial disease influenced by biological-behavioral-environmental factors. The reasons are as follows: (1) Excessive fat intake is one of the important factors that promote the formation of obesity. The intake and consumption of fat are balanced in two ways: fat oxidation for energy supply and reducing the intake of fat in diet through neural negative feedback. If intake and consumption cannot be balanced, it will promote the formation of obesity; (2) Low metabolic rate and obesity are genetic factors, such as obesity in India; (3) gene mutation. Gene mutations and variations related to obesity include leptin gene mutation, adiponectin receptor gene mutation, β3 receptor gene mutation and uncoupling protein gene mutation. There are diet control, exercise therapy and drug therapy to eliminate obesity. In view of the challenge of diet control and exercise therapy to spirit and perseverance, the most acceptable and expected method is to take diet pills.
2. The principle of common diet pills to lose weight
At present, drugs used to lose weight are mainly divided into three categories: drugs that inhibit appetite, drugs that inhibit intestinal digestion and absorption, and drugs that increase energy consumption.
1. appetite control drugs
By affecting the activity of nerve media, it can reduce appetite and increase satiety, thus reducing food intake. These drugs all act on the central nervous system, showing different degrees of weight loss, but their effects are limited and vary greatly among individuals.
1. 1 drugs affecting 5- hydroxytryptamine (5-HT).
Drugs that affect the 5- hydroxytryptamine (5-HT) system promote the release of 5-HT, inhibit its reuptake and increase the content of 5-HT in synaptic cleft, thus stimulating the satiety center of hypothalamus and suppressing appetite. These drugs include fenfluramine, dexfenfluramine, fluoxetine and sertraline. Can partially lose weight, but there are many adverse reactions, such as nausea, diarrhea, drowsiness, dry mouth, headache and dizziness, rotational nystagmus and so on. And long-term application can cause cardiovascular diseases such as heart valve damage and pulmonary hypertension. Therefore, in 1997, the FDA decided to ban the use and withdraw from the market.
1.3 mixed serotonin and norepinephrine reuptake inhibitors
Mixing 5-HT and norepinephrine reuptake inhibitors can inhibit the reuptake of 5-HT and norepinephrine at the same time, increase the concentration of these neurotransmitters in the brain, and thus inhibit appetite. These drugs include indole and its derivatives, such as indole, imidazole indole, sibutramine and so on. Sibutramine can also increase the excitability of the central sympathetic efferent nerve, thereby exciting β3 adrenoceptors, increasing glucose utilization and adipose tissue heat production, thereby increasing energy consumption and reducing body weight. Its addiction is low, and the common adverse reactions include headache, dry mouth, anxiety, insomnia, constipation and potential hypertension.
2. Drugs that inhibit intestinal digestion and absorption
High-fat diet is an important cause of obesity, so reducing the absorption of fat in gastrointestinal tract is another measure to control weight.
2. 1 lipase inhibitor
Orlistat is a potent, specific and long-lasting gastrointestinal lipase inhibitor, which acts on the stomach and small intestine, inhibits lipase and prevents fat molecules from decomposing into smaller absorbable triglycerides, thus reducing fat absorption and controlling weight. Adverse reactions mainly include mild and short-term gastrointestinal side effects, which affect the absorption of fat-soluble vitamins E and A. Fat-soluble vitamins should be supplemented appropriately. Its long-term efficacy and safety remain to be determined [6-8].
2.2 Glucosidase inhibitors
Acarbose can competitively inhibit glucosidase in small intestine, reduce the decomposition of polysaccharides and disaccharides to produce glucose, thus reducing the absorption of carbohydrates, and has the effect of reducing postprandial blood sugar and plasma insulin levels, but it can cause side effects such as flatulence, abdominal pain and diarrhea [9].
3. Drugs that increase energy consumption
3. 1 central stimulant
It can stimulate fat oxidation, increase energy consumption and reduce appetite. But it often takes a large dose to achieve the effect of losing weight. Such as ephedrine, theophylline and caffeine. However, patients who are sensitive to these drugs are prone to anxiety, excitement, insomnia and other adverse reactions, and patients with angina pectoris should use them with caution.
3.2 Adrenaline β3 receptor agonist
Selective β _ 3 receptor agonist can increase lipolysis of white adipose tissue and thermogenesis of brown adipose tissue, thus reducing fat storage; It can increase fat mobilization and energy consumption without affecting blood sugar level.
3.3 Hormone drugs
Thyroid hormone is a commonly used drug to produce heat. Supplementing thyroid hormone on the basis of diet control can accelerate the weight loss of obese patients.
Three. Domestic diet pills market
There are 70 million obese people in China, accounting for 14.6% of the total adult population. Among them, there are 930,000 obese people in Beijing 15-54 years old, and the market capacity of weight loss products in the city is 900 million yuan. 2 1 Century The market of slimming products in China can be divided into health food, tea, medicine, external use and equipment. Two new weight-loss drugs, orlistat and sibutramine, which were developed in the late 1990s, brought good news to obese patients with their exact curative effects and fewer side effects. In China, Qumei, Aoquqing and other weight-loss drugs with sibutramine hydrochloride as raw materials have been grandly listed, which once again set off the sales climax of weight-loss drugs. In 2000, Roche's new slimming drug Orlistat was announced to be listed in China, which also had a great impact on the whole slimming market.
The weight-loss drugs appearing in the domestic market are mainly divided into four categories: sibutramine, orlistat, Chinese patent medicine and L-carnitine.
1. A diet drug made of sibutramine.
In the United States, the trade name of sibutramine is Nometine, which was listed in the United States on 1998. Sichuan Taiji Group is the first pharmaceutical company in China to obtain the new drug certificate of sibutramine hydrochloride. It took three years to develop "Qumei" (sibutramine hydrochloride capsule). In June 2000, "Qumei" became the first national medicine quasi-brand weight loss drug approved by the State Pharmaceutical Administration. In addition, there are sibutramine hydrochloride capsules "Aoquqing" produced by Nanjing Changao Pharmaceutical Group, Kexiu produced by Nanjing Pharmaceutical, "Miracle Li Ting" introduced by Miracle in Guilin, Guangxi, and products of Hainan Sanyo Linde Company.
2. Orlister
Orlistat, with the trade name of Sanico, is owned by Roche and listed in the United States, 1999. L 1, in early 2000, he entered the China market with a sword-the import product license of the State Administration of Pharmaceutical Products, and applied for administrative protection for seven and a half years.
3. Chinese patent medicine
Chinese patent medicine diet pills continue to be popular. In recent years, a new type of plant-based slimming preparation with natural plant raw materials as the main component.
Green diet pills have sprung up in the international market, and the sales volume has increased year by year, forming a "green storm". At present, there are mainly NRG slimming capsules, Godian slimming series, slimming essential oil, Korean slimming soft gold, green slimming and Ogilvy lightning fixed-point slimming capsules on the market. Traditional Chinese medicine believes that the cause of obesity is related to "dampness, phlegm and deficiency", so fat people are dampness, phlegm and qi deficiency. Therefore, most Chinese patent medicines to lose weight start with regulating qi, expelling toxin, dispersing stagnation and inhibiting metabolism. In addition to losing weight, some of them also have the functions of lowering blood fat and preventing atherosclerosis.
4. L-carnitine
Since a man named "Dr. Ximu" introduced something called "L-carnitine" in the encyclopedia of Hunan Satellite TV, this uncommon term has been popular all over the country for a time. In shopping malls, L-carnitine products occupy a very important position, and there are dozens of diet pills added with L-carnitine. In newspapers and magazines, there have also been large-scale propaganda and advertisements. Searching for "L-carnitine to lose weight" on the Internet, there are probably millions of results. The most prominent physiological function of L-carnitine is to transport long-chain fatty acids in the body to mitochondria for oxidation to become the energy needed by the human body. Generally speaking, L-carnitine acts as a porter in the process of fat oxidation.
4. The bumpy road of diet pills
Diet pills are sought after by many consumers, but also accompanied by a lot of controversy, so the fate of most diet pills can be described as bumpy, and some even encounter huge claims. The amount of compensation for litigation.
Dinitrophenol (DNP) was discovered in 1930s, because it can consume and generate heat, which makes people lose weight quickly. Later, it was banned by the FDA because of blindness. Fen-Fen is a compound drug of Fenfluramine and Fentamine, which was listed in the mid-1990s. It was all the rage, but two years later, the drug was found to have caused fatal damage to heart valves and withdrew from the market, which triggered numerous lawsuits. Acomplia developed by Sanofi-Aventis was originally a new drug to treat diabetes and obesity. In 2007, it was first approved as a diet drug in Europe, but the same indication was rejected by FDA. The reason is that the drug increases the suicidal tendency of users. In 2007, rimonabant, a cannabinoid receptor antagonist, failed to pass the FDA's marketing approval in the United States, and then had to withdraw from the European market due to serious adverse reactions, including depression, anxiety and increasing the suicidal tendency of users. Affected by this, the research and development of several similar drugs that have entered the third phase of clinical practice have to be terminated early. Another diet drug, 5- hydroxytryptamine (5-HT), and sibutramine, a norepinephrine reuptake inhibitor, also suffered a similar fate. Based on the results of the safety assessment of sibutramine, CHMP of the European Medicines Agency suggested suspending its marketing license in the European Union. This randomized, double-blind, placebo-controlled study called "SCOUT" began in 2002 and lasted about 6 years. * * * This study involved 65,438+0,000 subjects who were over 55 years old, overweight or obese, had a history of cardiovascular disease or type 2 diabetes or were at risk of other cardiovascular diseases. Preliminary results show that sibutramine increases the risk of serious and non-fatal cardiovascular events, such as stroke or heart attack, compared with placebo. At this point, weight-loss drugs such as "Qumei" with sibutramine as the main raw material in the domestic market have been forcibly removed from the shelves.
Because some pharmacology of Chinese patent medicine is not clear enough, it is difficult to give a reasonable explanation on the mechanism of action, which hinders the further development of medicine to some extent. In addition, a Chinese patent medicine needs to be taken for a long time, and after stopping taking it, the body function will return to the state before taking it, which is very dependent on long-term medication.
As for L-carnitine, which is very popular in the market now, there is also constant debate. Manufacturers vigorously promote its important role as a fat porter, while some nutritionists and medical experts criticize it for stealing columns and seriously exaggerating the weight loss effect of L-carnitine. In fact, since the role of L-carnitine was discovered, there have been many experiments on whether it can lose weight, but so far, there is no reliable experimental evidence to prove its effectiveness. The University of Maryland Medical Center made a summary report on the research of L-carnitine, which wrote, "Although L-carnitine has been put into the market as a weight loss product, there is no scientific evidence that it has weight loss effect. In addition, one of the propaganda points of L-carnitine is "absolutely safe for human body". It should be pointed out that it is not rigorous to publicize something as "absolutely safe". There is no absolutely non-toxic food in the world. Eating too much sugar and salt, which are essential things in life, will also do some harm to the human body. L-carnitine, as a kind of substance advertised as nutrition, will still cause great potential harm to human body if taken in excess. Wang Zebin, a doctor of food engineering at Purdue University and a senior member of the American Food Technology Association, said: "The Office of Dietary Supplement of the National Institute of the United States has made a comprehensive summary of L-carnitine. This summary mentioned the research on various functions of L-carnitine, but did not mention losing weight. "It can be seen that the slimming effect of L-carnitine needs further scientific research.
Why is it so difficult to develop diet pills? Obesity is a complex chronic disease, which is closely related to physiology, heredity, diet, metabolism and other factors. No matter what the mechanism is, weight-loss drugs achieve 5% ~ 10% weight-loss effect, but also accompanied by corresponding risks and side effects. Obese people are at high risk of serious diseases such as heart disease, hypertension and diabetes. Obese patients will inevitably encounter different degrees of toxic and side effects when receiving long-term drug treatment. Unless special biomarkers are found in the future and targeted treatment is carried out, it is inevitable that diet drugs will harm patients. It is really not easy to develop high-safety diet pills. Otherwise, large pharmaceutical companies will not take it lightly and miss business opportunities. For people who are not obese, it is not worthwhile to cross the hurdle of diet pills because of the demand for beauty and so on. Coupled with the huge profits in the diet pills market, a number of manufacturers who dare to "take risks" to produce and sell diet pills have been born without any approval procedures, which has increased the confusion in the already poorly regulated diet pills market.
5. Face up to obesity and start with your own behavior habits-advocate behavioral therapy.
The findings in the report are often incomplete and sometimes even contradictory. Science is a process of constantly exploring and solving contradictions, and the study of obesity also belongs to this kind of scientific problem. When all the studies are combined, it is obvious that the problem of obesity cannot be solved by eating any kind of food or taking some diet pills. The occurrence of obesity involves many factors, environmental factors-eating habits, exercise habits; Biological factors-stored fat, higher satiety threshold, and even more sensitive taste buds; Economic factors-the global spread of junk food and so on.
At present, the most effective way is to change people's behavior, which starts with psychological and behavioral therapy, compared with dieting, exercise and taking diet pills to keep fit. The research of supporting behavioral weight loss therapy can be traced back to the behavioral analysis science developed and established by Harvard psychologist B. F.Skinner more than half a century ago. The basis of its concept-at present, scientists can't really understand the working mechanism of the human brain, but scientists can objectively observe and measure human behavior and its environment for many times, and then determine the relationship between environment and behavior according to the observation results. As early as the 1960s, behavioral studies on obesity and diet recognized that some basic conditions may improve the success rate of losing weight and keeping fit: strictly measuring and recording calorie intake, exercise and weight; Make some changes gradually and gently, not drastically; Pay attention to a balanced diet, moderate intake of fat and sugar, can not ignore the staple food; Set clear goals and do what you can; Cultivate lifelong eating habits instead of short-term dieting; Participate in group activities that can encourage dieters. These basic conditions were promoted by American Weight Watchers Company established by 1963, and were gradually recognized by everyone. In 2005, a study in Annals of Internal Medicine analyzed eight popular weight-loss programs and found that behavioral weight-loss therapy kept the weight loss of dieters at 3% during the two-year study period. Some related studies also show that the type of diet is not important, and the length of persistence is the decisive factor for effective weight loss.
Why can behavioral intervention take effect? Laurette Dube, a researcher in life psychology and marketing at McGill University School of Management, said that in our current environment, ingenious marketing methods are everywhere, stimulating our sensory desires all the time and attacking our fragile will barriers with attractive "information shells". The diet and exercise habits of family, friends and colleagues around us will have a certain impact on us. In essence, behavioral intervention is committed to reshaping the environment, pulling us out of the swamp of complicated information, sensory desires and drifting, and moving towards healthy eating and exercise habits. Du Bei said that when we really get the right information from enough channels, we can resist the temptation of food and keep in good shape.
Both the Office of the Public Health Bureau and the Centers for Disease Control and Prevention openly support behavioral therapy as an important weapon to fight obesity. Let's be initiated by the first lady of the United States, Michelle Obama.
Move, almost entirely relying on behavioral therapy, tries to alleviate the obesity problem of teenagers.
At present, the global obesity rate is the highest in history, and a large-scale weight loss plan will become the same topic all over the world. When deciphering obese The Secret Behind step by step, it seems that proper adjustment of diet and exercise habits is the most practical alternative. Of course, we expect the scientific community to give a comprehensive, complete and operable new answer to the obesity problem.