Meal frequency and the coffee diet: Exploring the dangers of skipping breakfast and the limitations of caffeine.

The "Skip Meal" Diet Method: The "Skip Meal" Diet is Everywhere. The "skip meal" diet is probably the most common weight loss method that comes to mind for most people. Whenever dissatisfied with their weight, they often blurt out, "I'm skipping my next meal; I'll starve myself to lose weight." Then, when they successfully achieve their goal of "skipping the next meal," they feel a great sense of accomplishment. Nowadays, young people commonly stay up late, often not resting until the early hours of the morning, and don't get up to eat breakfast. They only eat lunch and dinner each day, so the "skip meal" diet is widespread. A 2019 study on the dietary behavior of Chinese residents showed that the proportions of Chinese residents who skip breakfast, lunch, and dinner were 4.4%, 1.4%, and 0.2%, respectively. International studies have also reported that 36% of the population chooses to skip breakfast, making skipping breakfast the most frequently used "skip meal" diet method. II. The "Skip a Meal" Diet is Unreliable. Does "skipping a meal" actually help with weight loss? The theory behind the "skip a meal" diet is to control energy intake and lose weight by reducing meal frequency. However, this method's effectiveness may only exist in theory. Although some studies indicate that skipping breakfast for a short period can reduce total daily energy intake to some extent, and the decrease in total energy intake may be greater than the decrease in energy expenditure (negative energy balance), several long-term observational studies suggest that skipping breakfast has no significant effect on weight, and some studies even indicate that skipping breakfast may lead to weight gain. Based on current research results, there are no high-quality intervention studies to support the role of long-term breakfast skipping in maintaining a negative energy balance, or that long-term breakfast skipping leads to significant weight loss. Other studies indicate that eating three or more meals a day has little impact on food intake, while eating two or fewer meals a day has a negative impact on appetite control. III. The Dangers of "Skip a Meal" "Skip a meal, skip breakfast" can have many negative health effects. As early as the 1960s, studies indicated a link between daily meal frequency and overweight, high cholesterol, and impaired glucose tolerance. Recent meta-analyses have also shown that skipping breakfast is a risk factor for type 2 diabetes. Skipping a meal prolongs the intervals between the remaining two meals, putting the body in a short-term state of hunger. In this state, the body first uses glycogen to break down into glucose for energy, and then uses glucose converted from amino acids and glycerol through gluconeogenesis. When protein intake is insufficient, organ tissue protein is broken down to produce amino acids, leading to muscle loss. Muscle loss not only slows down the metabolic rate, making fat accumulation easier, but also causes loose skin, weakened immunity, reduced muscle endurance and core strength, and increased fatigue. International studies have confirmed that subjects who consumed carbohydrates in the morning performed better in exercise than those who fasted. In conclusion, the effectiveness of the "skip a meal" diet for weight loss is unknown, but its health risks are quite clear. A combination of diet and exercise is a more effective way to achieve long-term weight loss goals. Regular meals and maintaining a reasonable eating frequency not only help maintain good physical condition but also help prevent the development of long-term diabetes and cardiovascular diseases. The Coffee Diet: I. What is the "Coffee Diet"? The coffee diet is a recently popular weight loss method. It is claimed to have miraculous weight loss effects, with eye-catching headlines like "Lose 10 pounds in 7 days" and "Lose 8 pounds in a week" appearing everywhere online. Literally, the coffee diet involves drinking black coffee daily, utilizing its low-calorie, water-reducing, and bowel-promoting properties to achieve weight loss. This method caters to the widespread demand for simple and rapid weight loss, thus gaining widespread attention. II. Coffee Diet: Truth or Lie? According to existing research, chlorogenic acid, caffeine, and dietary fiber, which are abundant in coffee, may be the substances that make coffee effective for weight loss. Chlorogenic acid, as a polyphenolic phytochemical, has various effects such as anti-inflammation, prevention of diabetes, and promotion of gastrointestinal motility and gastric juice secretion; dietary fiber promotes gastrointestinal motility and gastric emptying. Caffeine, present in approximately 100mg per cup of coffee (240ml), is considered a key substance contributing to coffee's weight-loss effects. Studies have shown that caffeine can influence the body's energy balance by increasing metabolic rate, accelerating energy expenditure, promoting lipid oxidation and thermogenesis, thereby contributing to weight control to some extent. However, this effect is relatively limited: in one study, a caffeine intake of 300mg/day only resulted in an additional 79kcal of energy expenditure. According to the principles of weight loss, losing 1kg requires an average of 7200kcal of energy expenditure. Based on this comparison, it's clear that achieving a daily weight loss of 0.5kg by simply drinking about 3 cups of coffee is unrealistic. Furthermore, the weight-control effect of caffeine was observed in subjects with relatively low caffeine intake; there is currently no data to support this effect over long-term consumption. Therefore, the weight-loss effects of long-term coffee consumption should be viewed with caution. Third, the "coffee diet" is not as simple as it seems. Coffee is a natural beverage with a long history, but this does not mean it is harmless. Excessive caffeine intake can have certain effects on the body: high doses of caffeine can cause gastrointestinal symptoms such as nausea, vomiting, and stomach discomfort; a European study found a possible link between coffee consumption and chronic atrophic gastritis; excessive caffeine intake can also raise blood pressure, increasing the risk of hypertension, so people with hypertension should be more cautious when drinking coffee; although coffee has a stimulating effect, excessive consumption can disrupt sleep, leading to neuropsychiatric symptoms that can also be distressing. From the above analysis, it is clear that coffee for weight loss is not simply about drinking more cups; carelessness can easily disrupt normal life. If the principle is to avoid side effects, healthy adults should consume no more than 400mg of caffeine per day, and pregnant women should not exceed 300mg/day. In today's world of frequent food safety issues, we need to be more careful when choosing various weight-loss coffees. Reports indicate that some weight-loss coffees illegally add sibutramine, an appetite suppressant, to achieve weight loss. This substance can induce heart disease and stroke, posing a significant health risk. IV. How to Drink Coffee Properly: While coffee's role in weight management has been proven, relying solely on coffee for weight loss is unlikely to achieve the desired results. We can use coffee as a supplement to accelerate the body's energy metabolism, but the core of weight loss remains controlling energy intake and increasing energy expenditure. The correct way to use coffee is to choose high-caffeine black coffee, avoid adding sugar or other flavorings to prevent increased energy intake, and engage in some physical activity after drinking it to increase energy expenditure.