Possibly because of the reputation for rapid weight loss in seriously obese patients, several less expensive, liquid meal replacements have become commercially available for weight loss without medical supervision.
These products are not usually intended to replace every meal or all solid foods. These products are intended to help dieters lose weight quickly, though they often do little to affect long term lifestyle changes.
One of the more popular commercially available liquid meal replacements is called Slim Fast. The Slim Fast plan says dieters should eat one regular meal during the day and replace the rest with low-calorie shakes.
The shakes each provide one-third of the daily recommendations for a healthy diet. Slim Fast is one of the few liquid replacement plans that defends its plan with controlled clinical studies.
In a study done at the University of California, Los Angeles School of Medicine, 300 patients followed the Slim-Fast diet for 12 weeks. They lost an average of 15 pounds and 76% were able to keep at least 80% of the weight off by one year later.
However, most dieticians still maintain that a liquid replacement diet is not an appropriate substitute for a healthy lifestyle.