This is what Webmd says about Vlcd
https://www.webmd.com/diet/low-calorie-diets#1
And from Harvard Medical school
According to the Harvard Medical School, the least number of calories that one can consume a day while trying to lose weight is 1,200 a day for women and 1,500 a day for men (5). In light of this, the 800 calorie diet is not a safe eating plan for anyone unless they are under medical supervision.
And the NHS
https://www.nhs.uk/live-well/healthy-weight/very-low-calorie-diets/
Are you taking any supplements. These diets tend to be very low in calcium, vitamins esp D3 and the B vitamins, also folate and iron which you need for hemoglobin. This last one is important because if hemoglobin is low it affects your hematocrit blood parameter, and that will skew your bgl meter readings. So you may find your bgl appears to be high when it is in fact getting dangerously low. This is why we are concerned and why long term use of this type of diet is considered dangerous,
It is also important for this info to be discussed in this thread so that others reading this thread do not follow a harmful strategy that is misleading, not based on fact, and not supported by the experts. I have no problem with a low-cal diet that is time-limited. To make it an event-limited diet is problematic if the event expected does not occur. The loss or omission of important or essential nutrients becomes a severe issue the longer the diet is run, and damage may be occurring but going unnoticed. As has been mentioned, osteoporosis is one such condition that may not be apparent until physical damage forces medical intervention. Anemia is another one. Gall bladder/ bile duct. Please take the blinkers off,