Experts Debate Safety, Worth of Liquid Diets : Health: Manufacturers of very-low-calorie diets and their critics agree that the diets can be dangerous if not properly monitored. But they disagree on who should use them.
Liquid diets--which grew up quietly in the past decade as hospital treatment for the seriously obese and exploded in popularity in the late 1980s--might be losing some of their luster.
Manufacturers of such diet plans as Optifast, Health Management Resources and the over-the-counter protein drink, Slim-Fast, report a downturn in popularity after a year of soaring sales just as some lawmakers and health experts initiate public inquiries into the safety and effectiveness of the programs. Manufacturers, saying there is no clear explanation for the drop in business, say safety problems have not caused the decline.
But critics contend that although today’s liquid diets are much improved from the diet plans in the late 1970s that led to 60 deaths, even the modern diets have significant potential for misuse.
They say that very-low-calorie diets, or VLCDs, which usually take the form of protein drinks, are often prescribed by physicians who are untrained in their use and are frequently marketed to people who aren’t seriously overweight. They also charge that over-the-counter protein drinks might be misused, leading to severe health consequences.
Supporters of VLCDs, which include the directors of about 1,000 hospital-based programs, say the diets are safe when supervised by a physician and a team of nutritionists and behavior therapists. They say the diets have become an important tool in the treatment of obesity and that regular exercise and behavioral modification to teach the patient new eating habits often ensures moderate success.
In hearings before a House subcommittee earlier this month, health experts had plenty of criticism for many diet programs (including those that use prepackaged food), but urged special caution over liquid protein diets.
The diet business, which caters to at least 20% of U.S. adults at any given time, is out of control “with too many diet programs losing the balance between patient safety and making a profit,” said Rep. Ron Wyden (D-Ore.), who chaired the hearings.
“The worrisome trend is away from exercise and toward liquid protein diets, virtually all of them sponsored by physicians and hospitals, and so-called ‘fast diets,’ which ignore nutritional safety,” Wyden said.
He cited a commentary in the Jan. 5 issue of the Journal of the American Medical Assn. as a summary of the problems.
“Current very-low-calorie diets that provide essential nutrients and high-quality proteins are unquestionably safer than their liquid-protein predecessors,” wrote Thomas Wadden, a psychologist and obesity therapist at University of Pennsylvania School of Medicine, and two co-authors. “But the recent and zealous marketing of various formula products to physicians, as well as the public’s appetite for such diets, could lead to yet another round of complications and fatalities.”
Dr. Vincent Felliti, director of preventive medicine at Kaiser Permanente Medical Group in San Diego, said he has studied thousands of patients in the center’s Optifast program and has found minimal danger and a substantial rate of success.
Optifast, which became a sensation in 1988 when Oprah Winfrey announced she had dropped 67 pounds on the diet, and the HMR program compose 85% of the very-low-calorie-diet market, said a spokeswoman for the Boston-based HMR. But at least one dozen different liquid protein diets are offered through physicians’ practices and hospitals, Wyden’s committee reported.
Long-term studies on the effectiveness of the diets is scarce. But Felliti’s study of 2,200 Optifast patients showed that of those who complete the entire program, including behavior modification, 60% maintained two-thirds of their weight loss after 18 months. That figure is widely quoted within the industry. Winfrey says she has gained back 17 pounds.
“Taking weight off a person is a relatively safe process,” said Felliti. “What was inconceivable a decade ago can be done reliably and routinely now.”
In general, physician-monitored VLCDs involve consuming a liquid protein drink made of milk or egg for about 12 to 16 weeks, followed by a period of reintroducing normal foods and a long-term maintenance program to learn new eating habits, said Dr. Jack E. Rubin, associate director of the Health Development Institute at Century City Hospital, which operates a very-low-calorie diet called Therafast.
During the fasting phase, patients consume about 400 to 800 calories a day along with vitamin and mineral supplements and undergo regular blood and urine tests to monitor for adverse reactions to the fast, which manufacturers of the diets say are rare. The diets are called “protein sparing” because they are designed to allow the dieter to lose fat instead of protein.
“Basically very-low-calorie diets are designed for people 30 to 40 pounds overweight at the very least,” Rubin said. “Somebody who has 10 to 15 pounds to lose won’t lose that much weight (because) they don’t have that much fat to lose.”
And, he said: “These liquid diets are designed to be combined with behavior modification so that the patient can learn new techniques and avoid old ones that got them into trouble in the past.”
Charles Friend learned his lesson well. The Los Angeles man, 28, went on Optifast one year ago weighing 307 pounds and has lost 113 pounds. Friend still attends a weekly support group to maintain his weight loss.
“It’s a struggle,” Friend said. “But I’ve introduced exercise into my life. And the program has educated me about what I can eat. I like the fact that it was supervised by a doctor.”
But hospital and physician sponsorship is a cloak that may obscure the risks of very-low-calorie diets, say critics like Wadden.
According to Wadden, very-low-calorie diets are ripe for misuse due to:
* Consumption of the diets by people who are not severely overweight (less than 30% overweight) and who may be more at risk for serious side effects from fasting. Wadden also says the diets are less successful among those with moderate weight problems.
* Prescription of the diets by physicians untrained in their use.
Criticism that physicians who manage the diet programs need better training has rankled many in the field. Programs like Optifast and HMR say they require a multi-day physician training course that is adequate to ensure safety. But Wadden and others say that the complex nature of weight loss requires that physicians have more in-depth training.
“The training varies enormously,” Wadden said. “Some (programs) say, ‘yes, we train them,’ and that means sending them audio cassettes.”
The training courses offered by the manufacturers are inadequate to prepare a general physician to spot the rare, but life-threatening, complications that can arise when the body is subject to a fast, said Dr. C. Wayne Callaway, an endocrinologist and diet-book author at George Washington University and a key critic at the Wyden hearings.
Callaway, who represented the American Board of Nutrition at the hearings, said the complications include irregular heartbeat, fatigue, anemia, depression and gastrointestinal disturbances. Less serious side effects associated with the diets include temporary hair loss, dizziness, dry skin and bad breath.
“It’s not a totally innocuous procedure,” Callaway said. “It’s hazardous to venture a guess on these things, but I believe very few of them have appropriate training, such as endocrine training and nutrition training. A two-day course is not long enough if you’re dealing with a substantial risk.”
Wadden and Callaway claim that people are dying from the diets but that the incidents are difficult to pinpoint because they might be blamed on something else, such as a heart attack.
“I know that people probably die on these diets all the time,” Wadden said. “The problem is determining whether the fatality was attributable to other problems or to the diet.”
The manufacturers of the VLCDs angrily deny safety problems.
According to Jim Parsons, executive director of Optifast, manufacturers recognize the paucity of training for physicians in the treatment of obesity and are working with the American Medical Assn. to try and establish improved medical-school training and post-graduate courses in the field.
Further, he said, Sandoz Nutrition, the manufacturer of Optifast, would like the physicians offering the product to be specialized in the field of obesity treatment, as opposed to operating a more generalized practice.
“We would like them to be established as obesity experts,” Parsons said. “But obesity as a disease is not even recognized as such. It’s in its infancy. So you can’t really blame the medical schools for not addressing it. It doesn’t mean a physician shouldn’t be involved, and it doesn’t mean he can’t safely administer the program.”
Little evidence exists that the diets are unsafe. A recent study at the University of Southern California found that people on a 650-calorie-a-day liquid diet had no serious physiological changes that would appear to make the diet unsafe.
But, some slight changes seen in blood and urine indicate that fasting is a complex process and that patients should be monitored closely, says Dr. Ken Fujioka, director of the USC study.
“I agree that (physicians) should look at the patient’s lab values,” he said. “A lot of physicians aren’t trained in this but are doing it.”
The effects of fasting may be even more severe for an individual with less weight to lose, said Wadden, who claims some VLCDs are being offered to people without significant weight problems.
“This is an alarming practice because the vast majority of studies demonstrating the safety of very-low-calorie diets have examined their effects only in severely obese individuals, typically 50% or more overweight,” Wadden said in the JAMA article.
Consumers with only a minimal amount of weight to lose like the programs because weight loss is rapid--three to four pounds a week as opposed to one or two pounds a week on non-fasting diets, he said. But Wadden said the diet might prove to be “particularly hazardous” to people less overweight.
Mildly overweight people lose more lean body mass than do the very obese, he said. Loss of lean mass can cause cardiac function disturbances and damage to other organs. Severely obese can somewhat protect against that because of their large fat stores and other physiological characteristics, Wadden said.
Both the manufacturers of very-low-calorie diets and their critics agree that the diets can be dangerous if they are not monitored by a physician. Some operators of physician-monitored programs says the misuse of over-the-counter liquid diet products could prove disastrous for the entire field of obesity treatment.
Manufacturers of the over-the-counter diets caution individuals to eat one full meal a day. But unsupervised dieters might restrict their consumption of regular foods to a dangerous level and even use protein drinks exclusively, leading to complications, Wadden said.
Officials for the over-the-counter product Slim-Fast, which advises dieters to drink two protein shakes a day along with one balanced meal, say the product is not intended to mimic the physician-monitored diets.
“They are a very-low-calorie diets which should be monitored weekly by a doctor,” said Jean Elliott, a spokeswoman for the Thompson Medical Co., which makes Slim-Fast. “We are not that program. We are a moderately low-calorie diet, about 1,200 calories, the majority of the calories come from food. We are designed for the moderately overweight person who wants to drop a few pounds. You can misuse anything. But it is not designed to be your sole nutrition. We need to make that distinction.”
Much less costly than the hospital-run programs--which average about $3,000--Slim-Fast sales soared from $10 million in 1988 to $20 million last year, Thompson said.
The rapid growth of the industry is another reason it should be regulated, say Wadden and Callaway.
“I would like to see (regulations) that anyone who puts a diet on the market has to be able to show the safety,” Wadden said. “The second thing is to show long-term effectiveness.
“Right now there are no regulations whatsoever. I think the Food and Drug Administration considers these diets to be food, and there is nothing inherently dangerous about the diets just as there is nothing inherently dangerous about bread. The danger comes in how the diets are used.”
During the hearings earlier this month, Wyden threatened government intervention unless some of the safety issues can be clarified.
But the controversy might overshadow the potential of the diets to help people who have a serious medical need to lose weight, said Anne McGrath, a spokeswoman for the HMR diet.
“I think it’s great that hearings are going on and a lot of information is getting out,” she said. “If it helps alert people to any frauds or products where they are wasting their money, that’s good. But the downside risk is people throw up their hands and say why should I try any weight program if it isn’t going to work.”
