Low-Fat Dietary Pattern and Weight Change Over 7 Years: The Women's Health Initiative Dietary Modification Trial

ArticleinJAMA The Journal of the American Medical Association 295(1):39-49 · January 2006with40 Reads
DOI: 10.1001/jama.295.1.39 · Source: PubMed
Obesity in the United States has increased dramatically during the past several decades. There is debate about optimum calorie balance for prevention of weight gain, and proponents of some low-carbohydrate diet regimens have suggested that the increasing obesity may be attributed, in part, to low-fat, high-carbohydrate diets. To report data on body weight in a long-term, low-fat diet trial for which the primary end points were breast and colorectal cancer and to examine the relationships between weight changes and changes in dietary components. Randomized intervention trial of 48,835 postmenopausal women in the United States who were of diverse backgrounds and ethnicities and participated in the Women's Health Initiative Dietary Modification Trial; 40% (19,541) were randomized to the intervention and 60% (29,294) to a control group. Study enrollment was between 1993 and 1998, and this analysis includes a mean follow-up of 7.5 years (through August 31, 2004). The intervention included group and individual sessions to promote a decrease in fat intake and increases in vegetable, fruit, and grain consumption and did not include weight loss or caloric restriction goals. The control group received diet-related education materials. Change in body weight from baseline to follow-up. Women in the intervention group lost weight in the first year (mean of 2.2 kg, P<.001) and maintained lower weight than control women during an average 7.5 years of follow-up (difference, 1.9 kg, P<.001 at 1 year and 0.4 kg, P = .01 at 7.5 years). No tendency toward weight gain was observed in intervention group women overall or when stratified by age, ethnicity, or body mass index. Weight loss was greatest among women in either group who decreased their percentage of energy from fat. A similar but lesser trend was observed with increases in vegetable and fruit servings, and a nonsignificant trend toward weight loss occurred with increasing intake of fiber. A low-fat eating pattern does not result in weight gain in postmenopausal women. Clinical Trial Registration ClinicalTrials.gov, NCT00000611.
    • "In nutrition research, randomized controlled trials often address short-term interventions (evaluating many dietary hypotheses) in high risk groups with intermediate outcomes. There are only a few long-term intervention studies in nutrition research and all of them evaluating many dietary hypotheses in one trial [2][3][4]. Therefore, in nutrition research, well-designed prospective cohort studies are the main source of evidence to address decade long exposures populations with hard clinical endpoints [5]. Large prospective cohort studies have shown that 60–75 % of coronary and 36 % of cancer incidents can be explained by lifestyle factors such as unhealthy diets, overweight, obesity, physical inactivity, smoking and excessive alcohol intake [6]. "
    [Show abstract] [Hide abstract] ABSTRACT: Background There is a lack of systematic and comprehensive evaluations whether food intakes lower or increase risk of chronic diseases. In this network meta-analysis of prospective cohort studies, we aim to evaluate the effects of different foods on risk of chronic diseases. Methods/design We will search PubMed and EMBASE. This will be supplemented by a hand search and author contacts. Citations, abstracts, and relevant papers will be screened for eligibility by two reviewers independently. Prospective cohort studies will be included if they meet the following criteria: (1) evaluate the association of single food or food groups with all-cause mortality, cardiovascular diseases (incidence and mortality), cancer (incidence and mortality) or risk of type 2 diabetes. The following food groups will be evaluated: whole grains, refined grains, vegetables, fruits, nuts, legumes, eggs, dairy products, fish, red meat, processed meat and sugar-sweetened beverages; (2) include participants ≥18 years of age; and (3) study population were free of outcome(s) of interest at the onset of the study. To assess study quality, we will extract the following characteristics: study size, duration of follow-up, dietary assessment method, assessment of outcome and adjustment factors. If the identified studies appear sufficiently similar within and across the different comparisons between pairs of food groups, we will estimate summary-relative effects using random effects network meta-analysis. Subgroup and meta-regression analyses will be performed stratified by different follow-up cut-points, geographical region and sex. Discussion This is a presentation of the study protocol only. Results and conclusions are pending completion of this study. Our systematic review will be of great value to national and international authorities for evidence-based nutritional recommendation/guidelines, regarding the implementation of food-based dietary guidelines for prevention of chronic diseases. Moreover, our results can be implemented to develop new diet quality indices/scores. Systematic review registration PROSPERO CRD42016037069 Electronic supplementary material The online version of this article (doi:10.1186/s13643-016-0302-9) contains supplementary material, which is available to authorized users.
    Full-text · Article · Dec 2016
    • "" In an editorial response to this study published in JAMA, Dansinger and Schaefer [25] remarked " …despite some successes, overall the low-fat dietary approach has been a failure with the US public, which is in desperate need of effective obesity treatment and prevention strategies. " The WHI was also distinguished by a failure to show any benefit in the prevention of diabetes or cardiovascular disease [24, 26, 27]. It should also be emphasized that popular implementations of low-carbohydrate diets like the Atkins diet [28, 29] or Protein-Power [30] put no formal limit on caloric consumption on the assumption that the greater satiety of protein and fat will provide control of intake. "
    [Show abstract] [Hide abstract] ABSTRACT: The inability of current recommendations to control the epidemic of diabetes, the specific failure of the prevailing low-fat diets to improve obesity, cardiovascular risk, or general health and the persistent reports of some serious side effects of commonly prescribed diabetic medications, in combination with the continued success of low-carbohydrate diets in the treatment of diabetes and metabolic syndrome without significant side effects, point to the need for a reappraisal of dietary guidelines. The benefits of carbohydrate restriction in diabetes are immediate and well documented. Concerns about the efficacy and safety are long term and conjectural rather than data driven. Dietary carbohydrate restriction reliably reduces high blood glucose, does not require weight loss (although is still best for weight loss), and leads to the reduction or elimination of medication. It has never shown side effects comparable with those seen in many drugs. Here we present 12 points of evidence supporting the use of low-carbohydrate diets as the first approach to treating type 2 diabetes and as the most effective adjunct to pharmacology in type 1. They represent the best-documented, least controversial results. The insistence on long-term randomized controlled trials as the only kind of data that will be accepted is without precedent in science. The seriousness of diabetes requires that we evaluate all of the evidence that is available. The 12 points are sufficiently compelling that we feel that the burden of proof rests with those who are opposed. (C) 2015 The Authors. Published by Elsevier Inc.
    Full-text · Article · Jul 2014
    • "Interventions delivered indirectly (for example, by telephone) were only slightly less effective than those delivered face-to-face; this finding is supported by recent reports on the effectiveness of telephone-based interventions on physical activity and diet [59,60]. We observed a modest but significant increase in fish consumption, equivalent to an increase of 50 g or 0.35 portions of fish per week [8,28,35,36], which is important because of the beneficial role of fish in reducing cardiovascular risk [61]. In addition, there was a modest, but also significant, reduction in meat consumption, equivalent to a decrease of 60 g of meat per week. "
    [Show abstract] [Hide abstract] ABSTRACT: Retirement from work involves significant lifestyle changes and may represent an opportunity to promote healthier eating patterns in later life. However, the effectiveness of dietary interventions during this period has not been evaluated. We undertook a systematic review of dietary interventions among adults of retirement transition age (54 to 70 years). Twelve electronic databases were searched for randomized controlled trials evaluating the promotion of a healthy dietary pattern, or its constituent food groups, with three or more months of follow-up and reporting intake of specific food groups. Random-effects models were used to determine the pooled effect sizes. Subgroup analysis and meta-regression were used to assess sources of heterogeneity. Out of 9,048 publications identified, 67 publications reporting 24 studies fulfilled inclusion criteria. Twenty-two studies, characterized by predominantly overweight and obese participants, were included in the meta-analysis. Overall, interventions increased fruit and vegetable (F&V) intake by 87.8 g/day (P <0.00001), with similar results in the short-to-medium (that is, 4 to 12 months; 85.6 g/day) and long-term (that is, 12 to 58 months; 87.0 g/day) and for body mass index (BMI) category. Interventions produced slightly higher intakes of fruit (mean 53.7 g/day) than of vegetables (mean 41.6 g/day), and significant increases in fish (7 g/day, P = 0.03) and decreases in meat intake (9 g/day, P <0.00001). Increases in F&V intakes were positively associated with the number of participant intervention contacts. Dietary interventions delivered during the retirement transition are therefore effective, sustainable in the longer term and likely to be of public health significance.
    Full-text · Article · Apr 2014
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