节食指限制吃的食物份量，通常是以减肥瘦身作为目的。

开始减肥的初衷是为了身体健康，但随着人们对身材的看重度增加，节食成了减肥瘦身的一种途径。
然而节食减肥也成了社会物质丰富、社交发展进步的的一种代表。

Dieting is the practice of eating food in a regulated and supervised fashion to decrease, maintain, or increase body weight. In other words, it is conscious control or restriction of the diet. A restricted diet is often used by those who are overweight or obese, sometimes in combination with physical exercise, to reduce body weight. Some people follow a diet to gain weight (usually in the form of muscle). Diets can also be used to maintain a stable body weight.