Cambridge Diet

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Cambridge Diet








Research and general acceptance



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 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.

Cambridge diet

British version—4 stages


Reduce food intake gradually over a week or 10 days before beginning the diet

Losing weight (Sole Source program)

Women shorter than 5” 8”: three servings of Cambridge diet products daily and no other food

Women taller than 5” 8” and men: four servings of Cambridge diet products daily and no other food

Coffee, tea, and tap and bottled water allowed Drink at least 2 quarts of fluid per day 415 to 554 calories per day


After 4 weeks on the Sole Source program, add a meal of 3 oz. of lean white fish or poultry, cottage cheese, and a portion of green or white vegetables to the basic Cambridge meals

Total of 790 calories per day

Return, if necessary, to the Sole Source regimen for further rapid weight loss

Other options allow 1,000 or 1,200 calories per day for more gradual weight loss or to accommodate lifestyles

Weight maintenance

Begins at an intake of 1,500 calories per day

American version—5 programs


Designed for a weight loss of 2–5 pounds per week

820 calories per day: 3 servings of Cambridge Food for Life formula plus one 400-calorie conventional meal

A minimum of 8–10 glasses (8oz.) of water daily

Tea and coffee allowed, but not as substitutes for the water

Continue on the program until weight loss goal achieved

Fast start

For rapid and safe weight loss

Regimen is similar to the British Sole Source program

Do not remain on the program longer than 2 weeks at a time

Return to the Regular Program and contact a physician if experiencing headaches, nausea, or vomiting


Recommended for weight loss of 30 pounds or more, or for persons under doctor’s care for other medical conditions

Essentially the British Sole Source program, with the added provision that the dieter switch to the Regular Program when 10 to 15 pounds from weight goal


Essentially the use of the Cambridge’s Food for Life nutrition formula as a foundation, adding conventional foods while determining caloric level to maintain body weight

Lifetime nutrition

Use Cambridge diet products as meal substitutes for one or two meals a day, or as healthy snacks

(Illustration by GGS Information Services/Thomson Gale.)


United Kingdom and Western Europe

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 Mc-Lean 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 as well as the Cambridge Health and Weight Plan, were owned by the Howard Foundation between 1982 and 2005, 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.

The present Cambridge diet products available in the United Kingdom are sachets (packets) of powder, Mix-a-Mousse granules, liquid meals, and meal bars. The sachets are intended to be mixed with a half-pint of water (hot or cold) to produce a shake or soup. The sachets, which provide about 138 calories, are sold in boxes of 21 servings, a week’s supply. There are 12 different flavors including banana, mixed fruit, and chicken mushroom. The dieter may also purchase Mix-a-Mousse granules that add 20 calories to the powdered formula but give it a thicker texture. The liquid formula is available in a ready-to-drink version packaged as Tetra Briks—sealed cartons with straws. Tetra Briks come in banana or chocolate flavor. There are four flavors of chocolate-covered meal bars (caramel, chocolate, orange, and toffee), one of which can be consumed each day.

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


Body mass index (BMI)— The ratio between a person’s weight and the square of their height. A BMI over 25 is considered overweight; below 20 is considered underweight.

Cholelithiasis— The medical term for gallstones. People on a VLCD have an increased risk of developing gallstones from an increase of cholesterol content in the bile produced by the liver.

Cognitive behavioral therapy (CBT)— An approach to psychotherapy based on modifying the patient’s day-to-day thoughts and behaviors, with the aim of changing long-standing emotional patterns. Some people consider CBT a useful or even necessary tool in maintaining long-term weight reduction.

Ketosis— An abnormal increase in the number of ketone bodies in the body, produced when the liver breaks down fat into fatty acids and ketone bodies. Ketosis is a common side effect of low-carbohydrate diets or VLCDs. If continued for a long period of time, ketosis can cause serious damage to the kidneys and liver.

Very low-calorie diet (VLCD)— A term used by nutritionists to classify weight-reduction diets that allow around 800 calories or fewer a day.

as meal replacements or used in conjunction with regular food (e.g., sachet for breakfast, Tetra Brik for lunch, and normal dinner).

United States

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 10–11 g of protein per serving, 15 g of carbohydrates (derived primarily from fructose or fruit sugar), and 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 as well as flavor choices including 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, 13-15 g of protein, 18 g of carbohydrates, and 1 g 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 10 g of protein, 19-22 g of carbohydrates, and a low fat content.


British version

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:

  • Preparation: The dieter is asked to reduce food intake gradually over a week to 10 days before beginning the diet.
  • Losing weight: This initial step is called the “Sole Source” program and gives the dieter between 415 and 554 calories per day. Dieters are advised not to remain on the Sole Source program for longer than four weeks at a time. They are required to obtain a signed certificate from their doctor before they can begin the Sole Source program. Female dieters shorter than 5 ft 8 in take three servings of Cambridge diet products per day and eliminate other food; women taller than 5 ft 8 in and men are allowed four servings. Allowable beverages include coffee, tea, and tap or bottled water; forbidden beverages include alcoholic drinks, coffee or tea with milk added, fruit juices, and any drink containing sugar. The dieter is advised to drink at least 2 qt of fluid per day.
  • Stabilization: After four weeks on the Sole Source program, the dieter can add a meal of 3 oz lean white fish or poultry, cottage cheese, and a portion of green or white vegetables to the basic Cambridge meals for a total of 790 calories per day. The dieter can then return to the Sole Source regimen for further rapid weight loss. There are other options allowing the dieter 1,000-1,200 calories per day that are better suited for gradual weight loss.
  • Weight maintenance: Begins at an intake of 1,500 calories per day.

American version

The American version of the Cambridge diet is divided into five separate programs:

  • Regular: Designed for a weight loss of 2-5 lb per week, the Regular Program provides 820 calories per day: three servings of Cambridge Food for Life formula plus one 400 calorie conventional meal. The dieter is advised to drink a minimum of 8-10 8-oz glasses of water each day. Tea and coffee are allowed, but not as substitutes for the water. There is no stipulation that the Regular program is limited to four weeks.
  • Fast Start: Similar to the British Sole Source program, the Fast Start program is to be followed no longer than two weeks at a time. The dieter is advised to return to the Regular Program and contact a physician if they experience headaches, nausea, or vomiting.
  • Physician-Monitored: Recommended for persons who need to lose 30 lb or more, or who are under a doctor”s care for other medical conditions. It is essentially the British Sole Source program with the added provision that the dieter should switch to the Regular Program when he or she is 10-15 lb from their goal weight.
  • Maintenance: Uses the Food for Life nutrition formula as a foundation, while adding conventional foods until a caloric intake is determined to maintain an ideal weight.
  • Lifetime Nutrition: The Food for Life company recommends using the Cambridge diet products as meal substitutes for one or two meals a day, or as snacks indefinitely. This maintenance program is not endorsed by any government agency.


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, diabetes, or who need to lose more than 30 lb 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 be used by elderly persons, pregnant women, or nursing women only with caution.


VLCD s 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 VLCD s, is an increased likelihood of developing cholelithiasis, or gallstones .

There is also some financial risk to using the Cambridge diet. Although the American website states that the Physician-Monitored version is less expensive than VLCD hospital programs, all forms of the Cambridge diet cost $95–100 for a 15-day supply of the Original 330 Formula or $85–89 for a 15-day supply of the Food for Life formula. A case of six cans of the Original 330 Formula, supplying a total of 126 servings, is about $160. Although the cost per meal is between $1.25 and $1.45, the fact that the dieter must purchase at least a two-week quantity at a time is a risk for people who may not like the products well enough to remain on the diet.

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 the 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.


  • Have any of your patients ever tried the Cambridge diet? If so, how much weight did they lose? How long did they maintain the weight loss?
  • Have you ever supervised anyone on the “Physician-Monitored” form of this diet?
  • Do you know of anyone who has ever had health problems or adverse effects from following the “Regular” or “Fast Start” versions of the Cambridge diet?
  • Have you read any of the research studies published about this diet? If so, what is your opinion of their findings?
  • In your opinion, is cognitive behavioral therapy a helpful addition to a VLCD?

who has used the diet as a sole source of nutrition for several weeks. For the first time one realises 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.”

Research and general acceptance

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 VLCD s 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 in psychological medicine, dependence as a clinical phenomenon, and the misuse of benzodiazepine tran-quilizers as well as editing 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 VLCD s 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 (body mass index 30) 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 VLCD s are not superior in any way to conventional low-calorie diets (LCD s). One Canadian study reported in 2005 that a history of weight cycling tended to lower the health benefits that obese patients could receive from VLCD s, while a 2006 study carried out at the University of Pennsylvania in Philadelphia found that the use of liquid meal replacement diets (LMR s) with a daily calorie level of 1000–1500 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.



Howard, Alan, ed. Nutritional Problems in Modern Society London: J. Libbey, 1981.

Marks, John. The Vitamins: Their Role in Medical Practice. Lancaster, UK, and Boston: MTP Press, 1985.

Marks, John, and Alan Howard. The Cambridge Diet: A Manual for Practitioners. Lancaster, UK, and Boston:MTP Press, 1986.


Gilden Tsai, A., and T. A. Wadden. “The Evolution of Very-Low-Calorie Diets: An Update and Meta-Analysis.” Obesity (Silver Spring) 14 (August 2006): 1283–1293.

Hart, K. E., and E. M. Warriner. “Weight Loss and Bio-medical Health Improvement on a Very Low Calorie Diet: The Moderating Role of History of Weight Cycling.” Behavioral Medicine 30 (Winter 2005): 161–170.

National Task Force on the Prevention and Treatment of Obesity, National Institutes of Health. “Very Low-Calorie Diets.” Journal of the American Medical Association 270 (August 25, 1993): 967–974.

Nesheim, Robert O. “Current Methods of Assessing Food Intake.” Progress in Clinical and Biological Research 67 (1981): 49–57.

Nesheim, Robert O. “Measurement of Food Consumption— Past, Present, Future.” American Journal of Clinical Nutrition 35 (May 1982): 1292–1296.

“Not by Cereal Alone.” Time, August 17, 1979. Available online at,9171,909591,00.html (accessed March 2, 2007).

Saris, W. H “Very-Low-Calorie Diets and Sustained Weight Loss.” Obesity Research 9 (Suppl. 4): 295S–301S.


American Academy of Family Physicians (AAFP). Fad Diets: What You Need to Know. Leawood, KS: AAFP, 2005. Available online at (accessed March 2, 2007).

National Digestive Diseases Clearinghouse. Gallstones. Bethesda, MD : National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), 2006. Available online at

Partnership for Healthy Weight Management (PHWM ). Weight Loss: Finding a Weight Loss Program That Works for You Washington, DC: PHWM, 2006. Available online in PDF format at


American Academy of Family Physicians (AAFP). P.O. Box 11210, Shawnee Mission, KS 66207-1210. Telephone: (800) 274-2237 or (913) 906-6000. Website: http://www.aafp.org1.

Cambridge Direct Sales, 2801 Salinas Highway, Suite F, Monterey, CA 93940-6240. Telephone: (800) 4-HEALTH. Website:

Cambridge Health and Weight Plan, Clare House, Hunter”s Road, Corby, Northants, NN17 5JE. Telephone: (44) 1536-403344. Website:

Partnership for Healthy Weight Management (PHWM), c/o Federal Trade Commission (FTC), Bureau of Consumer Protection. 601 Pennsylvania Avenue, NW, Room 4302, Washington, DC. 20580. Website:

U.S. Food and Drug Administration (FDA). 5600 Fishers Lane, Rockville, MD 20857. Telephone: (888) INFO-FDA [(888) 463-6332]. Website:

Rebecca J. Frey, PhD

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Cambridge Diet

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