Exploring Common Dietary Misconceptions about Weight Loss: From the Energy Traps in Fruits to the Physiological Drawbacks of "Intermittent Fasting"

Many people believe that fruits, being low in calories and rich in vitamins and minerals, are ideal for weight loss. However, different types of fruits vary significantly in their energy content due to differences in water content and the content of energy-producing nutrients. Generally, fruits with higher water content and lower protein, fat, and carbohydrate content are lower in calories, such as apples, pears, grapes, strawberries, and watermelons. Conversely, fruits with lower water content and higher protein, fat, and carbohydrate content are relatively higher in calories, such as avocados, jujubes, jackfruit, coconuts, and durians. Furthermore, fruit energy is also related to its weight. While 100g of watermelon has relatively low energy, a medium-sized watermelon can contain several hundred kilocalories due to its considerable weight. While jujubes have a higher energy content per 100g, a single jujube only contains a few dozen kilocalories. Currently, there is no scientific research showing that eating five fruits a day can lead to weight loss. The person spreading this information simply specifies the quantity of fruit without specifying the size, type, or method of consumption; a closer look reveals its deception. Ignoring the energy differences caused by fruit size and type, eating only five low-energy fruits a day, resulting in lower energy intake than daily expenditure, would indeed lead to weight loss. However, most fruits are extremely low in protein and fat, and relying solely on fruit cannot meet the body's normal nutritional needs, inevitably leading to health problems in the long run. Furthermore, once a normal diet is resumed, weight will rebound rapidly. On the other hand, consuming five more fruits after a full meal actually increases energy intake, not only failing to achieve weight loss but also leading to weight gain. Even when freely combining fruit with other foods without restrictions, fruit intake should not be excessive. Most fruits contain 6%-28% sugar, primarily fructose, glucose, and sucrose. Fructose is highly sweet, stimulating appetite and leading to increased energy intake. Additionally, high fructose intake can promote fat synthesis, thus exacerbating obesity. However, using fruit for weight loss requires proper methods. Firstly, it's crucial to control fruit intake. The Chinese Dietary Guidelines recommend a daily fruit intake of 200-350g for healthy adults, roughly equivalent to one medium-sized apple to one medium-sized orange. Secondly, choose suitable fruit types, prioritizing low-energy and highly satiating fruits. Finally, choose appropriate ways to consume fruit. Fruit can be eaten as a snack, replacing some high-fat, high-energy foods between meals. Fruit can also be consumed before meals to raise blood sugar and increase satiety, thus reducing the amount of food consumed at main meals. Alternatively, fruit can replace staple foods at main meals, combined with other vegetables, meat, poultry, eggs, and dairy products. The concept of "not eating after noon" has recently resurfaced in the public eye, considered beneficial for health, and even used as a weight-loss "secret weapon." While many now believe this concept originates from Traditional Chinese Medicine, it actually originated in Buddhism. Several Buddhist texts, such as the *Sariputra's Questions Sutra* and the *Treatise on Breaking Through Appearances*, explain it. As a Buddhist precept, "not eating after noon" should be accurately understood as "not eating at inappropriate times," meaning not eating outside of permitted eating hours. Further research indicates that "not eating after noon" specifically refers to not eating between 12 noon and dawn the following day. Although the renowned ancient Chinese medicine practitioner Yu Chang later mentioned "Buddhism's abstaining from food after noon" in his medical case study *Yuyi Cao*, this was merely to illustrate the importance of mealtimes for health maintenance. Mr. Zhao Puchu, former president of the Buddhist Association of China, explained the significance of the Buddhist practice of abstaining from food after noon in his *Questions and Answers on Buddhist Common Sense*: "Monks' meals are provided by laypeople, and they only receive their alms once a day, eating at midday, which reduces the burden on laypeople. Furthermore, abstaining from food after noon is beneficial for spiritual practice." Nevertheless, Buddhism has its flexibility in implementing this practice; for example, Buddhists are allowed to consume medicinal foods. These medicinal foods refer to dinner, effectively serving the function of dinner to some extent, which aligns to some extent with the modern nutritional concept of "eat a good breakfast, a substantial lunch, and a light dinner." Therefore, the absolute "abstaining from food after noon" is like a mirage-it seems to exist, but may not be practically applicable. In ancient societies with a slower pace of life, when material needs were met, the three-meal-a-day system was widely accepted and gradually replaced the two-meal-a-day system as the mainstream. This reflects the scientific basis of the three-meal-a-day system. Compared to ancient people, modern society has a much later bedtime, and the energy consumption for physical and mental activities in the afternoon and evening is much greater than in ancient times. Therefore, appropriate snacks and dinners are even more important. Using "intermittent fasting" to extend the fasting period may have a weight-loss effect. In a short-term state of hunger, the body utilizes stored energy substances to ensure the energy supply to vital organs. First, it uses glucose from the breakdown of glycogen, and then uses glucose converted from amino acids and glycerol through "gluconeogenesis" for energy. When the body's protein intake is insufficient, the proteins in organ tissues, such as skeletal muscle, will be broken down to produce amino acids. The consumption of muscle tissue will lead to a series of symptoms such as decreased exercise endurance. However, the purpose of weight loss is to reduce excess body fat and increase muscle to achieve a better state of health. The "intermittent fasting" method loses muscle while losing weight, which contradicts the concept of losing weight for health. Studies have shown that practices like "intermittent fasting" (not eating after noon) to reduce meal frequency may not be significantly effective in reducing weight or increasing energy expenditure, and could even have many negative effects on the body. Reduced daily meal frequency and altered eating rhythms can lead to disturbances in leptin release, glucose and energy metabolism, and insulin sensitivity, potentially resulting in obesity and metabolic syndrome. Decreased meal frequency can also affect satiety, leading to increased binge eating, which may be associated with gastritis and other stomach conditions. Therefore, blindly following the "intermittent fasting" diet for weight loss is not advisable. Controlling calorie intake, eating moderately, and engaging in regular exercise are the right ways to lose weight.