The Cambridge diet is a commercial very low-calorie diet (VLCD). The diet was first used only in weight-loss clinics in the United Kingdom. In the early 1980s, the products associated with the diet (powder mix, meal bars, and liquid meals) started selling commercially in the United States and the United Kingdom. Formulations of the Cambridge diet in the United Kingdom differ from those that sold in the United States. In both the United Kingdom and North America, the Cambridge products are available only from distributors; they cannot be purchased over the counter at pharmacies or supermarkets.
A scientist at Cambridge University in England, Alan Howard, initiated the research that eventually lead to the development of the Cambridge diet in the 1960s. Howard became interested in obesity as an increasingly common nutritional problem. He worked together with Ian McLean-Baird, a physician at the West Middlesex Hospital, to create a formula diet food that would allow people to lose weight rapidly without losing lean muscle tissue, create a mild ketosis (a condition in which the body begins to use fat rather than carbohydrates as a source of energy), and contain enough vitamins, minerals, and micronutrients to maintain health. Howard and McLean-Baird also organized the first national symposium on obesity in the United Kingdom, which was held in 1968.
The formula that satisfied the researchers' goals was successful in helping people in hospital obesity clinics lose weight, but was not particularly appetizing. The researchers collaborated with food technologists to improve the flavor of the formula. After further testing with clinic patients, the Cambridge diet was marketed commercially in the United Kingdom in 1984, four years after it was available in the United States. In 1985, the Cambridge diet became available in Germany, France, and the Scandinavian countries, and in 1990 in Poland and Eastern Europe. The British company, Cambridge Manufacturing Company Limited (CMC), which manufactures the diet products associated with the Cambridge Health and Weight Plan, was owned by the Howard Foundation between 1982 and 2005. The Howard Foundation is a charitable trust established by Alan Howard to offer scholarships to international students and to fund research in obesity and nutrition. In 2005, the Cambridge Manufacturing Company was sold to its three senior managers and became Cambridge Nutritional Foods Limited.
Each sachet or liquid formula contains enough nutrients to be used as a complete meal. The meal bars can replace a meal as well, but have extra carbohydrates and should only be eaten once a day. The Cambridge diet products can be consumed exclusively as meal replacements or used in conjunction with regular food (for example, sachet for breakfast, Tetra Brik for lunch, and normal dinner).
Rights to the original Cambridge diet formula—a powder to be mixed in a blender with water or diet soft drinks—in the United States were obtained by Cambridge Direct Sales in 1979. After working to improve the formula's flavor, the diet was placed on the market in 1980. It was initially quite popular. The original version of the Cambridge diet is sometimes known as the “Original 330 Formula” in the company's promotional literature because Dr. Howard's first rapid weight-loss program called for a total daily consumption of only 330 calories, provided by three servings of the original powder formula (110 calories per serving). The nutrient ratio of the original formula is.35–.39 oz. (10–11 g) of protein per serving,.53 oz. (15 g) of carbohydrates (derived primarily from fructose or fruit sugar), and.04 oz. (1 g) of fat.
In 1984, Cambridge Direct Sales hired Dr. Robert Nesheim to develop Cambridge Food for Life products. Like the Original 330 Formula, Food for Life is a powder that comes in a can to be reconstituted with conventional foods. Food for Life is available in a super oats cereal version and includes flavor choices such as tomato, potato, mushroom, chicken soup, vanilla, chocolate, strawberry, and eggnog. Nesheim was specifically asked to meet guidelines for nutrition supplements established by the U.S. Food and Drug Administration (FDA). The company states that Nesheim “increased the protein and carbohydrate content for an extra margin of safety when used as the sole source of nutrition.” Food for Life contains 140 calories per serving,.47–.53 oz. (13–15 g) of protein,.64 oz. (18 g) of carbohydrates, and.04 oz. (1g) of fat.
The American company introduced a Cambridge nutrition bar in 1983, but was unsuccessful as the product had a short shelf life and lacked flavor appeal. Dr. Nesheim tripled the shelf life of the nutrition bars and improved their taste. Each bar contains 170 calories, with.35 oz. (10 g) of protein,.67–.78 oz. (19–22 g) of carbohydrates, and a low fat content.
The British version of the Cambridge diet cannot be used without the supervision of an official counselor, who “provide[s] a personal screening, advisory, monitoring and support service.” The counselors are trained and accredited by the company, and must follow a code of conduct in their dealings with customers. According to the company, most counselors are people who have successfully used the Cambridge diet themselves.
The British version of the Cambridge diet is for adults over the age of 16 and has four stages:
The American version of the Cambridge diet is divided into five separate programs:
The Cambridge diet claims to be a flexible plan that can be used as a VLCD for rapid initial weight loss and then modified to serve as a maintenance diet.
The Cambridge diet offers a rapid initial weight loss that compensates (for some dieters) the low calorie intake and other food restrictions. The American version also offers a peer support network and a self-instruction program based on cognitive behavioral therapy (CBT) called Control for Life.
People under a physician's care for high blood pressure, kidney or liver disease, or diabetes, or who need to lose more than 30 lb. (13.6 kg) should consult their physician before starting the Cambridge diet or any VLCD. The Cambridge diet should not be used by adolescents under the age of 16, and should only be used with caution by elderly people, pregnant women, or nursing women.
VLCDs in general should not be attempted without consulting a physician, and the Cambridge diet is no exception. The diet is not suitable for people whose work or athletic training requires high levels of physical activity. One physical risk from this diet, as from other VLCDs, is an increased likelihood of developing cholelithiasis, or gallstones.
A common criticism of the Cambridge diet, as of all VLCDs, is that it does not teach the dieter how to make wise food choices or other lifestyle changes necessary to maintain weight loss. The British website states rather defensively, “To these armchair critics [the Cambridge diet] is just another fad diet. Nothing could be further from the truth as anyone can vouch who has used the diet as a sole source of nutrition for several weeks. For the first time one realizes that vast quantities of food are not indispensable to life. It trains you to live without having food continually on your mind and the experience has a beneficial effect on most people.”
Proponents of the Cambridge diet claim that it is scientific and has been subjected to clinical research. However, there are no recent studies in mainstream medical journals specific to this diet. The British Cambridge diet website cites research papers from the late 1990s on VLCDs as a group, most of them concerning studies conducted in England, Sweden, and Finland. In addition, neither the two British researchers who originally developed the diet nor the American scientist who reformulated the British products for the American market in 1984 began their careers as weight reduction experts. John Marks was trained as a psychiatrist and published a number of books on psychological medicine, dependence as a clinical phenomenon, and the misuse of benzodiazepine tranquilizers as well as edited an encyclopedia of psychiatry. He wrote a book on the use of vitamins in medical practice in 1985, one year before the book he co-authored with Alan Howard on the Cambridge diet.
Robert Nesheim, the American physician credited with reformulating the original Cambridge diet products for the American market, began as a researcher in agricultural medicine. Dr. Nesheim acted as chief of research and development at the Quaker Oats Company until he retired in 1983. He believed in promoting products on the basis of taste, convenience, and cost.
Opinion is somewhat divided among medical and health care professionals on the subject of VLCDs as a group of weight reduction regimens, with European researchers tending to be more favorable to these plans than physicians in North America. The first report of the National Task Force on the Prevention and Treatment of Obesity on these diets noted that “Current VLCDs are generally safe when used under proper medical supervision in moderately and severely obese patients, and are usually effective in promoting significant short-term weight loss… [but] long-term maintenance of weight loss with VLCDs is not very satisfactory and is no better than with other forms of obesity treatment.”
In general, researchers in the United States and Canada maintain that VLCDs are not superior in any way to conventional low-calorie diets (LCDs). One Canadian study reported in 2005 that a history of weight-cycling tended to lower the health benefits that obese patients could receive from VLCDs, while a 2006 study carried out at the University of Pennsylvania in Philadelphia found that the use of liquid meal replacement diets (LMRs) with a daily calorie level of 1,000–1,500 calories “provide[d] an effective and less expensive alternative to VLCDs.” The American Academy of Family Practice (AAFP), a professional association of primary care physicians, discourages the use of VLCDs in general, and categorizes the Cambridge diet in particular as a liquid “fad diet.” The only study that reported that VLCDs are “one of the better treatment modalities related to long-term weight-maintenance success” was completed in the Netherlands in 2001. The Dutch researchers added, however, that an active follow-up program, including behavior modification therapy or cognitive behavioral therapy and exercise, is essential to the long-term success that they reported.
See also Calorie restriction ; Fad diets ; Gallstones .
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American Academy of Family Physicians (AAFP), PO Box 11210, Shawnee Mission, KS, 66207-1210, (913) 906-6000, (800) 274-2237, http://www.aafp.org .
Cambridge Health and Weight Plan, Clare House, Hunter's Road, Corby, NN17 5JE, United Kingdom, 44 15 3640 3344, http://www.cambridge-diet.co.uk .
Rebecca J. Frey, PhD
Revised by Laura Jean Cataldo, RN, EdD