Rainier Medical offers a medical intervention known as a very low calorie diet using a medically formulated liquid diet transitioning to an active weight regain prevention (maintenance) program. Today, I offer some of the research evidence on which it is based. We have heard a lot about basing things on science in the news lately. In medicine, there are evidence based practices, or those based on research, and non evidence based practices. When available, evidence based is best. You might think that every time you get a treatment recommended to you that it is evidence based, but that is not always possible for various reasons. The last time I heard the statistic, it was about 17% for the percentage of care that was actually evidence based. I won't venture into the reasons why it is not higher here. Following is a summary I made, in lay terms, of a review article on the role of these diets, their outcomes, safety, and a discussion on perhaps using them in a more widespread fashion. There is a link to the free full text article available to the public in the International Journal of Obesity.
The following is paraphrased from a review article. A review article is an article in which the authors have taken into account all the individual peer-reviewed articles and synthesized them. The statements in parentheses are my own and not part of the article.
Type 2 diabetes mellitus (T2DM) is closely linked to diabetes and is the main contributor to rising healthcare costs (which individuals bear more and more with high deductibles and co-insurance plans). Most individuals with T2DM have a BMI>25 and about half have a BMI>30. With a BMI>35, 20% of all men and 11% of all women have known diabetes. (Many people have diabetes and do not know it. Men have more complications with a given amount of excess weight than women, even though studies show that more women are trying to lose weight than men.)
Although previous guidelines have retained a 5-10% weight loss target, with the increasing severity of obesity, new guidelines set target of >15-20% weight loss for those with BMI > 35 or BMI>30 with serious medical complications such as T2DM. (This is crucial as most anti-obesity medications have less expected weight loss than this.) Since the current medical treatment of obesity in usual care patterns rarely shows this amount of weight loss, some guidelines are simply recommending bariatric surgery (But, is there a better way than conventional current treatment?).
With conventional dietary advice, people with obesity usually have less weight loss than people without T2DM. This is likely because many medications for diabetes cause weight gain, people have already engaged in usual diabetes education. (Also, the high insulin, insulin resistant state can prevent weight loss. T2DM is just one of many conditions that prevents weight loss or causes weight gain, it is just the most often studied.)
Articles were searched electronically between 1946 and 2015 for total diet replacement diets, low energy liquid diets, or very low calorie diets. The diets ranged from 300 to 1000 calories per day using formulas diets and lasted 4 to 52 weeks.
Baseline weights ranged from 99-126 kg (BMI 30-42.6 kg/mxm). Total weight loss ranged from 9 to 15 kg in those with T2DM and 8 to 21 kg in those without T2DM.
The greatest rates of weight loss were mostly in studies with more restrictive VLCDs. Study duration did not appear to influence overall weight loss. (stay on program, do not modify, and get it over with!)
Transient events including constipation, dizziness, dry skin and bad breath were reported in two studies. There was one case of severe low blood sugar in a patient with T2DM. There were 2 heart attacks (non fatal) that were determined to not be related to the diet.
Substantial weight losses were achieved in all studies. It was less than expected for 100% compliance. (What can Rainier Medical do to help with tolerability and adherence?) Factors related to the amount of weight loss varied including the duration the diet, the age, gender, and overall health status.
Rates of weight loss were consistent, at 2.7 to 7 pounds per week. Inclusion of a 300 calorie meal at different time points in one study correlated to a lower rate of weight loss.
The metabolic benefits of bariatric surgery appear to be reproducible by the very low calorie diet / low energy liquid diet. One study achieved reversal of T2DM within 4 years of diagnosis. (I have a podcast on this. Stay tuned!)
Acute entry restriction has been shown to improve plasma glucose even before significant weight loss occurs. (This is why medication is reduced at the start of the program.)
Formula diets, with a period of total diet replacement, are widely used and popular outside healthcare settings. There is some published evidence that they are successful, with little or no evidence for serious safety problems, although large-scale safety testing has not been undertaken (which is why screening and medical monitoring is recommended). Despite clear evidence for efficacy and lack of safety concerns, there is continuing reluctance by medical staff and in clinical guidelines to support the use of formula diets. (Why is this?) Guidelines published in the USA and Australia advocate the use of very low calorie diets for weight management but recommend these should be delivered in medical settings.
Beliefs that more intensive interventions and rapid weight loss lead to greater weight regain, are not supported by evidence from controlled trials. Comparison of weight regains, following either a 12 week rapid weight loss program or a 36 week gradual program, found no difference in the proportion of weight regain at 144 week follow up. Effective strategies for long term weight-loss maintenance have been described, even in people with knee osteoarthritis (presumably limiting exercise).
An article in The New England Journal of Medicine predicted in 2019 that by 2030, 50% of Americans would have obesity. There is no practical reason to expect bariatric surgery to make a dent in this number. Past studies have shown the medical community to be reluctant to adopt evidence based interventions. A very low calorie liquid formula diet is an effective, safe, evidence based medical intervention for the prevention and reversal of Type 2 Diabetes and the treatment of excess weight. It should be administered in a medical setting after a screening process with medical monitoring by a medical professional trained and experienced in doing so.
My goal in providing this summary of this review article is to provide transparent evidence to inform you on all of your healthcare options. I recommend an individualized discussion as this is not medical advice, only a platform for informing you to engage in joint medical decision making and be sure you are aware of the evidence for certain obesity medicine treatment protocols.
Take Back Your Health,
Valerie Sutherland, MD