What is the minimum calories a day to survive?

What is the minimum calories a day to survive? This question relates to the lowest energy intake needed to support essential bodily functions and basic health.

The absolute minimum to support basic life functions is your basal metabolic rate, the calories your body uses at rest for breathing, circulation, and cell maintenance. For most adults, this often falls near 1100–1600 calories, but it varies with sex, height, weight, age, and body composition. Consistently eating below your estimated basal needs can impair hormone balance, mood, reproduction, and immune and metabolic health. Most medical very-low-calorie diets operate around 800 calories and require professional supervision, regular monitoring, and limited duration. For sustainable weight loss, targets are usually set above basal metabolic rate, creating a moderate deficit instead of pushing toward bare survival levels.

To understand your own baseline needs safely, use our calorie requirement calculator to estimate basal and maintenance calories based on your personal details.

Read more related questions in our Calorie Calculator FAQs.