Many people have probably heard of the term intermittent fasting, but what exactly is it? Does intermittent fasting have any benefits for health?
The “Chinese Guidelines for Nutrition Therapy of Overweight/Obesity (2021)” points out that “intermittent fasting,” also known as intermittent energy restriction, is a dietary pattern that involves fasting or limiting energy intake according to a specific schedule during certain periods.
However, many people tend to take intermittent fasting to extremes, with some believing that it means starving oneself, thinking that the harsher they are on themselves, the better the results.
This understanding is not only unhealthy but can also be harmful to health. The medically defined intermittent fasting should be a scientifically appropriate form of dieting. For example, the 5:2 intermittent fasting scheme involves a 7-day cycle where one eats normally for 5 days and limits energy intake to 2000-2400 kilocalories (kcal) per day; on 2 days, food intake is restricted to one-third or one-quarter of normal eating.
The goal of intermittent fasting is to control weight through scientific dieting, helping to avoid obesity-related diseases. As everyone knows, obesity can ruin everything; it impacts not only appearance but also leads to a variety of health issues. Obese patients, due to insulin resistance, are at a higher risk of developing type 2 diabetes. Moreover, the likelihood of obese individuals suffering from hypertension, high cholesterol, stroke, and coronary heart disease is also very high.
Besides intermittent fasting, there is another method of dieting that many people have likely heard of, which is fasting after noon.
Fasting after noon, as the name implies, means not eating anything after lunch, thus changing the typical three meals a day into two meals.
Is skipping one meal really beneficial for health?
On February 22, 2022, a team from the Department of Liver Surgery at Peking Union Medical College Hospital, led by Mao Yilei and Yang Huayu, published a study titled “Randomized controlled trial for time-restricted eating in healthy volunteers without obesity” in the journal Nature Communications.
The research team recruited 82 healthy non-obese individuals and divided them into three groups: the first group could only eat between 6:00 and 15:00, with fasting during the rest of the time; the second group could only eat between 11:00 and 20:00, with fasting during other hours.
The third group could eat at any time. (Members of the first and second groups were only allowed to drink water, soda water, and unsweetened tea or coffee during fasting periods.)
The study found that among non-obese individuals, compared to other time periods, controlling the eating window to the morning (any 8 hours within 6:00 to 15:00) was more effective in improving insulin resistance, obesity, and related metabolic issues. It alleviated inflammation levels and enriched gut microbiota without affecting sleep quality or appetite.
Based on this study alone, the conclusion is clear: fasting after noon is beneficial for health, particularly in improving insulin resistance and obesity-related metabolic issues. In other words, fasting after noon helps improve blood sugar levels. However, does this mean that patients already diagnosed with diabetes can adopt this method for better blood sugar control?
The answer is no.
First, diabetes patients who skip dinner are at risk of low blood sugar.
Many diabetes patients often need to use blood glucose-lowering medications, whether oral medications or injectable insulin. Before medication, doctors advise that meals should be regular and not to take medications without eating, or eat too late. The reason is that as long as medication is taken, there is a risk of low blood sugar. Low blood sugar is more serious than high blood sugar. Severe low blood sugar can lead to consciousness disorders, brain edema, and even threaten life.
To prevent low blood sugar, diabetes patients must manage their medication scientifically and maintain a proper eating schedule.