Yes, the Denmark or Danish diet program does help a person to lose 20 pounds in 13 days. This Danish diet is an extremely low calorie diet and it can be called a crash diet. The weight loss will be rapid but not sustainable. The diet plan species what foods should be eaten at different meals. At times only one meal per day is allowed. Others may include only water, tea or coffee. The rationale behind this crash diet plan is by varying the amounts of foods at meal times will lead to weight loss. This diet is not for vegetarians but anyone following this diet is bound to lose weight quickly.