Do people consume fat or protein first

When the body lacks energy, it will first consume glycogen, then break down fat, and finally break down protein for energy supply. This process is mainly influenced by factors such as exercise intensity, duration, and dietary status. During the early stages of exercise or low-intensity activities, the body mainly relies on blood sugar and muscle glycogen for energy supply. When glycogen reserves are depleted, triglycerides in adipose tissue are broken down into free fatty acids and enter the bloodstream, becoming the main source of energy. Fat oxidation requires sufficient oxygen participation, so moderate to low-intensity aerobic exercise can better promote fat consumption. Under extreme hunger or long-term calorie deficit, the body may break down muscle protein through gluconeogenesis to provide energy. This situation usually occurs when the body fat percentage is extremely low or after continuous fasting for more than 72 hours. Protein breakdown can lead to muscle loss and affect basal metabolic rate. It is recommended to avoid this situation through regular eating and moderate protein intake. maintaining a reasonable calorie deficit and balanced nutrient intake is the key to healthy weight loss. It is recommended to control the daily calorie deficit within 500 calories, ensuring a protein intake of 1.2-1.6 grams per kilogram of body weight, and maintaining muscle mass through strength training. Choosing low-intensity aerobic exercises such as brisk walking and swimming, lasting for more than 30 minutes at a time, can increase the proportion of fat supply. Avoid long-term use of extremely low calorie diets and regularly monitor changes in body fat percentage and muscle mass.