Fat is seen by many as an enemy to health, but a recent study published by the American Heart Association shows that eating the right kind of fat could save more than 1 million lives worldwide.
The role of fat is misunderstood
Dr. Dariush Mozaffarian, lead author of the paper and dean of the Friedman School of Nutrition Science and Policy at Tufts University in the U.S., led the research. The researchers conducted a comprehensive analysis of data from 186 countries in 2010 and found that more than 710,000 deaths from heart-related diseases (such as hypertension, cerebrovascular disease, and coronary heart disease) globally were due to insufficient intake of omega-6 polyunsaturated fatty acids; about 250,000 deaths were due to excessive intake of "bad fats." The study was the first to confirm that insufficient intake of polyunsaturated fatty acids leads to an increase in heart-related diseases.
Both Zhang Jian, director of the Geriatric and Clinical Nutrition Department at the National Institute for Nutrition and Health of the Chinese Center for Disease Control and Prevention, and Zhou Chunling, vice president of the Nutrition and Food Safety Branch of the Chinese Geriatrics Society, stated in interviews that people currently have many misconceptions about fat intake.
Misconception 1: All high-fat foods are unhealthy. One reason people avoid high-fat foods is that they lead to obesity. In fact, the unsaturated fatty acids in some foods are beneficial when consumed in moderation.
Misconception 2: Reducing cholesterol intake will lead to fewer diseases. "Many people, in order to lower their cholesterol, almost never eat high-cholesterol foods like liver and egg yolks," Zhou Chunling said. Currently, no research has proven a direct causal link between dietary cholesterol and cardiovascular diseases such as atherosclerosis.
Misconception 3: "Controlling intake" means not eating any at all. In Zhang Jian's view, the Chinese diet is falling into a vicious cycle: "controlling" means not eating any at all. For example, many people avoid lard because of its 40% saturated fat content, but in fact, lard also contains 40% monounsaturated fatty acids, which are "good fats."
Misconception 4: Not eating meat or using less oil can prevent hyperlipidemia. Hyperlipidemia is divided into hypertriglyceridemia, hypercholesterolemia, and mixed types. The first type is common in China, and the main dietary factor is excessive intake of staple foods (i.e., carbohydrates), not excessive fat intake.
Inadequate fat intake is actually dangerous
As one of the three major macronutrients essential to the human body, fat provides energy, protects internal organs, maintains body temperature, and participates in various metabolic activities. Zhou Chunling points out: "Excessive fat intake can lead to obesity and a series of metabolic-related diseases, but insufficient intake can also be harmful to health."
Malnutrition. Fat is involved in human metabolism. When total fat intake is insufficient, it can easily lead to energy malnutrition. This is especially true for the elderly, whose food intake decreases and digestive abilities decline, making them more prone to nutritional deficiencies.
Skin diseases such as eczema. A deficiency in essential fatty acids can also cause skin diseases like eczema and rough skin.
Reduced metabolic capacity. Phospholipids themselves are involved in the transport and metabolism of fats, cholesterol is an important raw material for the synthesis of sex hormones and vitamin D, and plant sterols can promote the metabolic absorption and utilization of fats. A long-term deficiency of these lipids can hinder the body's fat metabolism.
Lipid-soluble vitamin deficiency. Insufficient fat, especially essential fatty acids, can lead to deficiencies in lipid-soluble vitamins A, D, and E, resulting in diseases like xerophthalmia, night blindness, and osteoporosis.
In addition, fat in the legs and hips of women serves as a form of energy storage. During pregnancy, this fat can be mobilized as fuel to support fetal growth and prepare for lactation. For men, the secretion of androgens also depends on fat. If one excessively adheres to a low-fat diet for a long time, it can easily lead to fatigue and weakness.
Mastering the principles of fat intake
The general principle for fat intake is to control the total amount of fat, and the intake ratio of polyunsaturated fatty acids, monounsaturated fatty acids, and saturated fatty acids should ideally be controlled at 1:1:1. Specifically, Zhou Chunling recommends choosing vegetable oils like peanut oil and rapeseed oil as the main cooking oils, using them alternately, and controlling the daily amount to about 20-25 grams (about two and a half tablespoons). Prioritize foods with lower saturated fat content, generally choosing in the order of fish, poultry, beans, meat, eggs, dairy, and nuts. When eating meat, fish is the first choice, followed by poultry, then red meat. Ensure a total intake of 2-3 liang (about 100-150 grams) of meat per day, but eat less processed meat like ham and sausage. One whole egg and one carton of milk per day. Nuts are high in fat; a handful of shelled nuts contains about the same amount of fat as 15 grams of cooking oil, so don't eat too much at once—a small handful is enough.