Eating too much of this kind of food may be more harmful to your health than eating oil.

On February 24, the Population Health Research Institute (PHRI) of McMaster University and Hamilton Health Sciences Corporation in Canada conducted an epidemiological study on 137,851 urban and rural residents living in 20 countries on five continents. Through dietary habit surveys, they found that a low-quality carbohydrate diet, that is, high glycemic index (GI) foods, would significantly increase the risk of cardiovascular disease and all-cause mortality.

Are carbohydrates good or bad?

Not all carbohydrate foods are created equal, and diets rich in low-quality carbohydrates can lead to a shorter lifespan, while diets rich in high-quality carbohydrates such as fruits, vegetables and legumes are beneficial to health.

The study was published in the prestigious New England Journal of Medicine.

The researchers recorded detailed information about participants' habitual food intake (i.e., food frequency) using a 28-question food questionnaire and obtained the glycemic index of carbohydrate foods from food databases such as the International Glycemic Index Table.

The study found that participants who already had cardiovascular disease had a 50% increased risk of major cardiovascular events (non-fatal myocardial infarction, stroke, or heart failure) or death if they ate a high GI diet; for those with no history of heart disease, the proportion also increased by 20%.

Particularly for obese participants (BMI ≥ 25), the risk of disease is higher. Among the countries surveyed, the impact of a high GI diet was more significant for 44,845 Chinese participants. In other words, Chinese people eat too much refined rice and flour.

The glycemic index (GI) is calculated based on 100g of food, with GI70 being a high GI food. High GI foods are digested quickly in the gastrointestinal tract after consumption, have a high absorption rate, and release glucose quickly, leading to a rapid increase in blood sugar; low GI foods stay in the gastrointestinal tract for a long time, have a low absorption rate, and release glucose slowly, which can prevent blood sugar from rising after a meal. Low GI foods may also be beneficial to intestinal flora, as the indigestible dietary fiber in them is not digested by the human body and can be left for microorganisms to enjoy.

Low GI foods are high-quality carbohydrate foods.

The glycemic index (GI) of the seven major categories of carbohydrate-containing foods are: beans 42, non-bean starches 93, non-starchy vegetables 54, fruits 69, fruit juice 68, dairy products 38 and sugary drinks 87. The GI of rice is about 83, and that of steamed buns made from enriched flour is about 88.

Most fruits, vegetables, beans and whole-grain foods have a low glycemic index, while white bread, white bread, rice and potatoes have a high glycemic index.

Eating large amounts of low-quality carbohydrates is a common problem not just in China, but around the world.

A low GI diet helps reduce the risk of cardiovascular disease and death. In addition, studies have shown that eating low-quality carbohydrates may be more harmful than eating most fats in the diet. In other words, eating too much high GI food has a greater impact on health than eating oil. This requires us to fundamentally change our mindset and consider the GI index and the needs of intestinal microorganisms when choosing a diet, and not eat too refined food.

DOI: 10.1056/NEJMoa2007123