Men in hunger test

The video discusses a study on the effects of starvation on the human body, conducted by the New York Medical College for the US Army. Conscientious objectors volunteered to participate in experiments testing different diets, ranging from a healthy intake of 1800 calories to a starvation level of 400 calories per day.

What is the minimum calorie intake for health mentioned in the text?

What is the starvation level of calorie intake defined in the text?