Can you tell me more information about these: low calorie dieting and metabolism.?

Tricky: First, KG (a bit high) or pound (very low weight) ? then.... wt (lb) x 10 = calories used (90lb=900,low) 4000 calories net in or out is a pound gained/lost. when weight goes lower, you use less calories. daily. also, with starvation there's a tendancy to lose muscle; makes losing weight harder. https://www.kickstarter.com/projects/1775472781/devils-diet