A very low calorie diet consists of 8,000-1,500 calories per day. If you have a BMI over 30 (which your physician will refer to as “obese”), a very low-calorie diet can allow you to lose about 3 to 5 pounds per week, for a total weight loss of 44 pounds over 12 weeks. Those with diabetes, high blood pressure, and high cholesterol can benefit from losing weight in that amount. Low-calorie diets work temporarily, but in the long run, they’re not as effective as modest diets. You need to change your lifestyle after you go off a diet, by eating healthily and engaging in regular physical activity.
A very low-calorie diet of 600 calories a day may be able to reverse type 2 diabetes, preliminary research suggests. Eleven people who had been diagnosed with type 2 diabetes within the past four years slashed their calories for eight weeks, sticking to a diet of liquid diet drinks and non-starchy vegetables. Three months after going off the diet, seven were free of diabetes.
References:
https://www.webmd.com/diabetes/news/20110624/very-low-calorie-diet-may-reverse-diabetes
https://www.diabetes.co.uk/news/2016/mar/very-low-calorie-diet-can-reverse-type-2-diabetes-for-six-months-94107931.html
https://www.insider.com/study-low-calorie-diet-helped-control-diabetes-without-medication-2020-11#:~:text=A%20very%20low%2Dcalorie%20diet%20has%20been%20shown%20to%20help,their%20blood%20sugar%20without%20medication.
https://www.webmd.com/diet/low-calorie-diets#1
https://care.diabetesjournals.org/content/39/5/808