Obesity is a nutritional metabolic imbalance disorder, which refers to a physiological condition in which a person’s body has relatively high levels of fat or is overweight.

According to the survey results, at least 1/5 of the world’s population is above normal weight. Researchers at the International Agency for Research on Cancer (IARC) reviewed more than 1,000 studies on the relationship between body weight and cancer risk and showed that obesity increases the risk of 11 types of cancer.

Weight loss is a behavior aimed at reducing excess body fat and weight. About 3/4 of cancers caused by overweight and obesity can be avoided by weight loss. Weight loss includes a variety of lifestyle modifications (diet, yoga, exercise, fitness, etc.), weight loss medications and foods, and surgical procedures.

With the deepening of research, many dieters have realized that dietary modification, appropriate aerobic exercise and a regular life are more conducive to increased energy consumption and fat metabolism. Clinical studies have also shown that scientific and reasonable nutritional therapy combined with exercise intervention is still the most effective and safest basic treatment.

Analysis of the efficacy and composition of weight-loss health food

China’s health food is rich in variety, large in scale and diverse in function, and by searching the information on the official website of the State Food and Drug Administration, as of November 2018, a total of 17,470 types of health food have been approved to be listed in China, of which 16,690 types of domestically produced health food and 780 types of imported health food are available. Among the health food approved for listing, 401 kinds of domestic health food, accounting for 2.29% of the total health food, and 10 kinds of imported weight-loss health food, accounting for 0.057% of the imported health food, were searched by inputting the keyword “weight-loss” in the health care function.

1.1 Analysis of formula components of weight-loss health foods
By analyzing the data information, there are 429 main raw materials used in weight-loss health food (401 domestic and 10 imported), and the cumulative frequency of use is 2854 times.

The top 20 most frequently used ingredients are lotus leaf, cassia seed, L-carnitine, zelda, hawthorn, poria, green tea, gibberellic acid, L-carnitine tartrate, magnesium stearate, konjac, tea polyphenols, lotus leaf extract, starch, cellulose, heshouwu, malt, dextrin, glycerol and calcium pyruvate.

The more frequently used ingredients are analyzed below.

As can be seen from Table 1, lotus leaf has the highest frequency of use, with 46.47% of weight loss health foods using this raw material. Lotus leaf is rich in alkaloids, and its lipid-lowering and weight-loss efficacy has been recognized.

Lotus leaf can effectively reduce blood lipid levels, inhibit the growth of body mass, and prevent cardiovascular and cerebrovascular diseases such as high blood fat, high blood sugar and atherosclerosis. In addition to this, cassia seeds also have the effects of lowering blood pressure, blood lipids, blood sugar, regulating immunity and antibacterial.

1.2 Analysis of the efficacy components of weight-loss health foods
The efficacy components of weight-loss health food present diversity, through the data statistics, 411 weight-loss products, labeled with the efficacy components of 331, not labeled with the efficacy components of 80, most of the weight-loss health food contains more than two kinds of efficacy components, as shown in Figure 1, of which the efficacy of more components are carnitine, total flavonoids, thea polyphenols, total anthraquinones, and calcium pyruvate, which are the five kinds of efficacy components of weight-loss health food, the total frequency of the occurrence of the efficacy components in the weight loss category. The total frequency of these five efficacy ingredients in weight-loss food products is 410 times.

Carnitine (L-carnitine) as a weight loss health food has the highest proportion of efficacy components, reaching 31.87%. L-carnitine can enhance the activity of fatty acid oxidase in the body, can effectively control body weight and reduce blood lipid level, improve the metabolic syndrome of abdominal obesity, dyslipidemia, anti-fatigue and other functions, can induce the gene expression of enzymes related to lipolysis to stimulate adipocytes to increase the level of lipolysis and β-oxidation, so as to achieve the effect of lipid-lowering and weight loss.

In addition, L-carnitine is enough to promote the secretion of digestive juices, improve the activity of digestive enzymes, adjust the gastrointestinal function, which is widely used in weight loss health food, athletes’ food, baby food and nutritional supplement for the middle-aged and the elderly.

Flavonoids with weight loss effects mainly include rutin, flavonoids, soy isoflavones, etc. Flavonoids can regulate blood lipids, antioxidant effect, and at the same time, can be a strong removal of overtime and late at night or strenuous exercise produced by free radicals, thus eliminating body fatigue, anti-aging.

Soy isoflavones are a class of important phytoestrogens, with a unique crystalline structure, has an important role in human health, weight loss and lipid lowering, antioxidant, anti-tumor and other functions, in recent years has also been widely used in weight loss health food ingredients.

Anthraquinone is the general name of a class of organic compounds, widely found in medicinal plants, such as rhubarb, cassia seeds and senna leaves are rich in such substances, anthraquinone has weight loss effect, mainly through the promotion of intestinal peristalsis, accelerate lipid excretion of the excretion pathway and inhibit the synthesis of triglyceride and lipid cholesterol in the body, lowering the level of blood lipids pathway.

Calcium pyruvate, as a dietary supplement, has the functions of accelerating fat consumption, weight loss and fat scavenging, and reducing body weight; Zhou Yong and other studies have shown that moderate exercise combined with calcium pyruvate supplementation is able to effectively improve the blood lipid level and body composition of obese female college students.

Problems in the current weight loss health food

2.1 Adding prohibited drugs
The most common added drugs in weight loss drugs are 3 types:
① Appetite suppressants, whose main ingredients are fenfluramine and sibutramine. Appetite suppressants act on the central nervous system to suppress appetite, which has considerable side effects on the body, and long-term use may even cause heart valve damage and pulmonary hypertension and other problems.

The U.S. Food and Drug Administration officially banned its use for weight loss in September 1997; Sibutramine hydrochloride suppresses appetite and may cause serious side effects such as increased blood pressure, increased heart rate, anorexia, insomnia, and liver function abnormalities. Phenolphthalein, on the other hand, directly stimulate the intestinal mucosa, long-term use will damage the enteric nervous system.

② Laxatives or diuretics, such as orlistat, rhubarb, senna, etc. is to speed up the peristalsis of the intestinal tract to reduce the time that food stays in the gastrointestinal tract and the rate of absorption. Diuretics such as diet tea, by increasing the number of excretion, forcing away the body’s normal body fluids rather than excess fat, will cause dehydration.

(iii) Agents that help burn fat and calories. The principle is to promote the body’s metabolism and protein breakdown and increase consumption, thereby achieving weight loss. This is also a drug that acts on the central nervous system and is potentially very harmful.

Many weight-loss health food manufacturers illegally add these prohibited ingredients in order to achieve the efficacy of their products, and the long-term consumption of these ingredients can seriously damage human health and even put lives at risk.

2.2 Risks of taking the product
Weight-loss tea is the most common weight-loss products, weight-loss tea containing anthraquinone is not recommended for long-term use, especially for those who are weak in spleen and stomach, they should be more cautious.

Meal replacement diets have become increasingly popular in recent years. These diets are low in calories and can effectively reduce weight, lower blood pressure and reverse diabetes. However, a recent study published in the UK Daily Telegraph suggests that meal replacement diets may affect the normal beating of the heart.

Summary and Outlook

At present, obesity has become a global health problem, and the morbidity and mortality of bone and joint disease, fatty liver, diabetes, high blood fat, high blood pressure, sleep apnea syndrome, and cardiovascular and cerebral vascular disease, which are closely related to obesity, have risen sharply, seriously affecting people’s health.

In the face of the serious situation of obesity incidence increases year by year, with the rise of the fitness craze and the continuous pursuit of health, the demand for weight loss health food will continue to increase, and the research will be further in-depth. Weight loss health food should not only focus on its weight loss efficacy, but also safety, so that it can be fully recognized by the market and become the best choice for weight control.