Cambridge Diet Research Articles

Differential Trajectories in Altered Insulin Sensitivity Following Weight Loss and Their Impact on Circulatory Amino Acids: Results from the PREVIEW: New Zealand Sub-study (OR27-07-19)

ObjectivesMetabolite profiling studies have consistently identified altered circulatory concentrations of amino acids (AAs) in individuals with heightened risk of type 2 diabetes and cardiovascular diseases. Of the changes reported to date, the branched-chain amino acids (BCAA) may be a reliable biomarker of disease risk and have been reported to be elevated many years prior to the onset of diabetes. We hypothesised that energy restriction-associated weight loss in pre-diabetes individuals would result in altered profile of circulatory AAs, including BCAA, with the changes correlating with the improvement in insulin sensitivity. MethodsPre-diabetic individuals (confirmed using the American Diabetes Association criteria) aged 25–70 years with BMI > 25 kg/m2 recruited into the New Zealand arm of the PREVIEW diabetes prevention trial, participated in an 8-week weight reduction program, with a requirement to lose ≥ 8% initial body weight using a commercial low-calorie diet (LCD, Cambridge Diet, UKTM). Among those who succeeded, current analysis based on available samples (n = 168) from baseline (week-0) and end of weight loss (week-8). Serum free AA concentrations measured by ultra-high pressure liquid chromatography (UPLC) and all other metabolites measured using standard assays. ResultsSignificant weight loss (11.1 ± 0.2% from baseline) accompanied improved insulin sensitivity and lipid profile. BCAA concentration positively correlated with insulin resistance measured at week 0 and 8, correspondingly (P < 0.05). Although the concentration of some AAs reduced significantly from week 0 to 8 (P < 0.05), reduction in fasting BCAA concentration was not significant (P > 0.05). However, regression analysis demonstrated that independent of weight loss, every 1.0 standard deviation (SD) reduction in BCAA concentration was associated with improvement in insulin sensitivity by 1.9 SD (P < 0.05). ConclusionsAs expected, dietary energy restriction-associated weight loss in individuals with pre-diabetes contributes towards normalisation of insulin sensitivity. Further, the responsiveness of AA and BCAA profiles to weight loss may be beneficial for monitoring and overseeing disease risk and improvement. Funding SourcesThis research was funded by the EU 7th Framework Programme; the New Zealand Health Research Council; the Food and Health Programme Seed Funding, University of Auckland; and AgResearch Limited (the Strategic Science Investment Fund). Cambridge Weight Plan, Ltd, UKTM provided the commercial LCD.

Weight maintenance after a very low calorie diet (VLCD) weight reduction period and the effects of VLCD supplementation: A prospective, randomized, comparative, controlled long‐term trial

To evaluate the efficacy of a structured very low calorie diet (VLCD) weight reduction/weight maintenance behaviour programme on weight maintenance in obese patients (BMI > or = 30 kg/m2). Prospective, randomized, controlled intervention trial. University out-patient obesity clinic. A total of 114 obese patients from the waiting list were invited to participate in the structured weight reduction/weight maintenance programme lasting for 64 weeks. Sixty patients agreed to participate. All 60 patients were placed on a Cambridge 330 kcal day-1 diet during the first 12 weeks. Fifty-two were subsequently randomized to either a well balanced hypocaloric diet (1600 kcal day-1), of which 220 kcal were provided by two sachets of Cambridge diet (group 1), or the same energy provided by the same principal diet (group 2) during the following 52-week weight maintenance period. During the VLCD period, the mean body weight decreased significantly from 112.4 +/- 19.8 to 91.6 +/- 17.7 kg (P < 0.0001). Seventy-one per cent of the weight loss was fat. During the weight maintenance period the average body weight increased significantly in group 1: 8.0 +/- 8.2 vs. 12.3 +/- 9.7 kg in group 2 (P < 0.0001). After the 64-week treatment period the mean body weight in group 1 was 93.7 +/- 18.1 kg and significantly lower compared to 109.9 +/- 23.8 kg in group 2 (P = 0.008). Compliance was high: 87% completed the VLCD period and 75% completed the whole 64-week treatment programme. Very low calorie diet as part of the dietary allowance during the weight maintenance programme partly prevents weight regain. This finding can be translated into practical treatment recommendations.

Drug therapy after very-low-calorie diets

Very-low-calorie diets (VLCDs) are effective at reducing weight, even in patients who have often failed with conventional diets. Maintaining weight lost by means of a VLCD remains a clinical challenge. Attempts to prevent weight regain by dietary reeducation or by more formal behavior-modification techniques are not easily applicable to large numbers of patients and are not always successful; the use of drugs to maintain and improve upon initial VLCD success could be of real clinical value. Pharmacological treatment of obesity has evolved in recent years with the development and licensing of potent serotonin agonists, such as dexfenfluramine (dF), acting as nonstimulant anorectic agents. Thermogenic drugs are not yet as advanced in clinical development and evaluation but offer the prospect of increasing energy output in the reduced obese patient. Drugs used to treat obesity need to be effective, to be safe, not to exhibit drug tolerance, and ideally, to be shown to reduce morbidity or mortality from obesity, particularly because treatment will need to be prolonged. Such requirements are not unique for treating obesity, they are similar for drugs used to treat other metabolic diseases such as hypercholesterolemia or diabetes. VLCD followed by dF has been shown to be effective. A double-blind trial randomized 45 patients who had successfully completed 8 wk of treatment on the Cambridge diet to either placebo or dF 15 mg twice daily for 26 wk. Patients continued on a diet giving 60-75% of daily energy needs.(ABSTRACT TRUNCATED AT 250 WORDS)

Compliance with a low calorie diet for two weeks and concurrent and subsequent mood changes

One hundred people intending to use the Cambridge Diet for a 2 to 3-week period were asked about their weight, dieting, eating behaviours and demographic factors and completed the Profile of Mood States, Multiple Affect Adjective Checklist, Beck Depression Inventory, Locus of Control Scale, Dutch Eating Behaviour Questionnaire and Dieting Motivation Questionnaire. They were also asked to complete the Multiple Affect Adjective Checklist and the Profile of Mood States daily for a period of 14 days and on a further two occasions at weekly intervals. Complete follow-up data was collected on 47 of the original participants. In these people, a slight decrease in depression occurred during the diet. Approximately one fifth of the people who attempted to use the diet for a two-week period succeeded in complying with it fully. None of the factors assessed reliably predicted compliance with the diet.

Responsible and Irresponsible Use of Very-Low-Calorie Diets in the Treatment of Obesity

AMERICA'S most celebrated weight loss was announced on November 15,1988, when Oprah Winfrey disclosed to her 18 million television viewers that she had lost 30.5 kg (67 lb) in 4 months by consuming a medically supervised very-low-calorie diet ( New York Times . November 24,1988:B17). Ms Winfrey's announcement sparked a frenzy of interest among the nation's dieters, reminiscent of that which greeted the appearance of the liquid protein diets in 1976 and 1977 1 and the Cambridge Diet in the early 1980s. 2 Sadly, consumption of these diets was inadequately supervised; at least 58 deaths were reported among users of liquid protein products 1,3 and 6 deaths in persons who consumed the Cambridge Diet. 2 Current very-low-calorie diets that provide essential nutrients and high-quality proteins are unquestionably safer than their liquid protein predecessors, as noted in a timely report prepared by the American Medical Association's Council on Scientific Affairs. 4 But the

Diet-induced changes in sex hormone binding globulin and free testosterone in women with normal or polycystic ovaries: correlation with serum insulin and insulin-like growth factor-I.

The purpose of this study was to investigate the effect of calorie restriction on serum concentrations of sex hormone binding globulin (SHBG) in women with normal or polycystic ovaries (PCO) and to examine the possible role of insulin and insulin-like growth factor-I (IGF-I) in mediating changes in SHBG levels. Six normal subjects with mean (SD) body mass index (BMI) 25.5 (2.2) and five subjects with PCO (BMI 36.1 (3.7)) were studied before and after 2 or (PCO only) 4 weeks of a very low calorie diet (330 kcal/day; Cambridge Diet). In both normal women and patients with PCO there was a twofold increase in SHBG concentrations after 2 weeks and this was sustained in the PCO subjects for a further 2 weeks. The rise in SHBG was accompanied by a fall in free testosterone concentrations. There were parallel changes in serum insulin and IGF-I concentrations which decreased during the diet and there were significant negative correlations of SHBG with insulin in both normal subjects (r = -0.62) and women with PCO (r = -0.60). In addition, serum concentrations of an insulin-dependent small molecular weight (34 kDa) binding protein for IGF-I (IGF-BPI) increased significantly during dieting in both groups and were negatively correlated with serum insulin (controls, r = -0.56; PCO, r = -0.68) and positively correlated with serum SHBG levels (controls, r = 0.69; PCO, r = 0.63). In summary, these data indicate that in both normal subjects and those subjects with PCO, calorie restriction results in a highly significant increase in SHBG concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Loss of fat, water, and protein during very low calorie diets and complete starvation

The magnitude and composition of weight loss obtained in obese women on two forms of very low calorie protein-supplemented diets (Cambridge diet, Dresden drink) as well as by complete starvation has been investigated. With the VLCD, nitrogen equilibrium was reached on the 10th day of fasting, the cumulative nitrogen balance also being compensated. Nearly half of the body weight loss is due to loss of fat. In order to assess the benefit of fasting regimes, we propose to measure at least two parameters which are independent of each other, e.g., nitrogen balance and total body water. Both types of VLCD were equally effective, safe, and acceptable in achieving rapid body weight reduction.

Weight reduction methods of college women

Weight reduction attitudes and practices were obtained from a sample of 400 female students. Forty-eight percent reported using a weight loss program since admission to college. The programs most often selected included hypocaloric diets and exercise. Although the majority of subjects rated hypocaloric diets and exercise as good methods for weight reduction and indicated that they would recommend them to others, these methods supported the slowest rate of weight loss. Evidently, the side effects and costs of the other programs offset the rapid weight loss. Other methods, in descending order of use, included the Cambridge diet, drugs, weight loss clinics, and low-carbohydrate diets. Improved appearance was most often given as the reason for losing weight.

The Cambridge Diet-Reply

In Reply.— Dr Howard's letter not responsive to our criticisms of the Cambridge Diet. We made no claim that the diet is fundamentally unsafe. In fact, we specifically noted that it may not be inherently dangerous but that danger arises from the manner in which the diet used. A major problem with the Cambridge Diet that we addressed the manner in which it marketed to the public—without assurance that its users will obtain the close medical supervision that required with all very-low-calorie diets. 1 Dr Howard contends, on the basis of survey data and data from the FDA, that the Cambridge Diet safe. This contention rests on the assumption that there has been a complete reporting of all deaths associated with the diet—a very risky assumption. It precisely the manner in which the diet marketed that prevents Cambridge International from obtaining accurate

The Cambridge Diet

READERS of both Time (March 14, 1983, pp 91-93) and Newsweek (Feb 28, 1983, pp 75-77) learned recently of "a new scientific breakthrough that works faster and is more effective than you ever thought possible." This "breakthrough," heralded in three-page advertisements, is the Cambridge Diet. Since "more than three million overweight Americans have already discovered the Cambridge Diet Plan," and millions are likely to as a result of these ads, the medical community would be well advised to familiarize itself with the diet and the controversy surrounding it. The Cambridge Diet is one of several very-low-calorie diets (300 to 600 kcal/day) currently available in this country. The goal of these diets is to induce the largest, most rapid weight loss possible, while preserving lean body mass by the provision of varying amounts of high-quality protein and carbohydrate. This was the same goal of the liquid protein diets of 1976 and

An ominous left-sided pelvic mass in a young woman associated with the Cambridge Diet

An ominous left-sided pelvic mass in a young woman associated with the Cambridge Diet