With a VLCD program, one can expect to lose up to 20% of body weight. However, liquid protein fasting regimens are difficult for many people. Many that begin a program do not complete it. Excluding the patients that drop out within the first week or so, the most widely-quoted figure for VLCD programs is a 60% completion rate (or 40% drop-out rate). If a company says that it has a 90% completion rate, you can be pretty sure it's not accurate.

Typically, about 70-80% of those on medically monitored fasting programs are women. Their average age is 34 years. Medicare and insurance firms will reimburse patients for the cost of the physical exam and any tests related to obesity conditions, but they generally do NOT reimburse for the supplement formula itself. Most VLCD plans span 6-18 months, including the maintenance phase. The total cost usually ranges from $1,600 to $3,500. The high cost of medically-monitored VLCDs is an inherent inhibitor to the number of dieters that can afford to pay for them,

BestDietForMe.com estimates that about 500 hospitals and clinics in the United States offer a modified fasting VLCD program. About 200,000 Americans were enrolled in these programs in 2004.

MD-based and hospital-based VLCD programs today use more nutritionally complete supplement than those used in the late 1970s, and are therefore safer. Also, weekly or biweekly in-person medical monitoring and monthly lab tests, as well as initial screening out of unsuitable fasting candidates, lessens the chances of unsafe fasting and harmful side effects, enhancing these program’s credibility and justification of relatively high cost to the public.

VLCD plans are highly structured programs for people that have a significant (not cosmetic) amount of weight to lose. The good thing about these programs is that you are closely monitored by a staff of experienced clinicians and will rarely get into trouble on them. You are monitored via weekly doctor visits and monthly lab tests, and there is a long-term maintenance plan to help you keep the weight off. Virtually all the providers in the field have long-term outcome data, and have a long track record in the medical weight loss arena.

The increase in the number of weight loss surgeries in recent years has spurred demand for VLCD programs and for fasting supplements. Many patients are put on the supplement to lose weight PRIOR to the surgery, to make the operation go smoother, and many patients also use the supplement AFTER the surgery, to assist in the long-term weight maintenance phase.

A specific diagnosis is always required for a VLCD patient's insurer to reimburse them for part of the total program. The cost of the supplement is not covered (which may represent as much as 50% of the total bill). On average, the VLCD supplement alone accounts for 47% of the total cost of the program, and is not reimbursed by health insurance.

VLCD providers say that the most common diagnoses pertaining to their patients include... obesity, type 2 diabetes, hyperlipidemia, hypercholesterol, hypertension, hypertriglycerdemia, degenerative joint disease, hyperglycemia, arthritis, and sleep apnea.