An ad libitum, very low-fat diet results in weight loss and changes in nutrient intakes in postmenopausal women

OBJECTIVES: To determine whether a very low-fat diet (<15% of energy intake) consumed ad libitum during an 8-month period can achieve weight loss of 5% to 10% of initial body weight while still providing adequate intakes of other essential nutrients. DESIGN: Longitudinal, 8-month, ad libitum, free living, very low-fat diet trial. SUBJECTS: Fifty-four of the sixty-four healthy postmenopausal women recruited completed the entire study (age 59+/-8 years, BMI=29.6+/-6.3). Twenty-four of these women used hormone replacement therapy, thirty women did not. INTERVENTION: Weekly sessions aimed at teaching and reinforcing a very low-fat intake diet for eight months. MAIN: outcome measures Body weight, percent body fat, waist-to-hip ratio, resting energy expenditure, respiratory quotient, and nutrient intakes derived from 7-day food records at the beginning and at 2, 4, 6, and 8 months of the study.Statistical analysis performed Repeated measures analysis of variance and Tukey post hoc analysis were used to analyze significant differences in mean data (P<.05). RESULTS: Fat intake decreased from 33.2+/-7.5% to 11+/-4% over the 8-month intervention period (P<.00001). Weight loss was 6.0 kg+/- 4.2 kg (P<.000038), an 8% weight change, and decrease in percent body fat of 2.7%+/-0.2% (P< or =.000046). Weight correlated better with the self-reported fat intake (r=0.321, P<.01) than the energy intake (r=0.263, P<.05) at baseline. Fiber intake increased from 16 g+/-0.6 g to 23 g+/-0.2 g (P<.0005). All micronutrient intakes remained at or above preintervention ranges, except for a decrease in vitamin E intake from 8.1 mg+/-4.0 mg to 3.7 mg+/-1.1 mg (P<.0005) on the very low-fat diet and linoleic acid from 6.3%+/-1.5% to 2.5%+/-0.7% (P<.000001) with no significant reduction in linolenic acid. Hormone replacement was not associated with the amount of weight loss. APPLICATIONS: This study demonstrates that adherence to a very low-fat diet consumed ad libitum causes weight loss in the 5% to 10% range and a reduction of body fat. These reductions, along with the observed decreases in fat intake, are associated with improved health outcomes. Because of the decreased vitamin E and n-3 fatty acid intake, emphasis on foods high in these nutrients may need to be encouraged for those consuming a very low-fat diet.     

Nutrient and food intake in obese women on a low-fat or low-calorie diet

The low-fat group consumed significantly fewer calories from fat and more calories from carbohydrate at both 6 and 12 months than the low-calorie group, but their fat intake was still about twice their goal at both 6 months (39 gm per day) and 12 months (46 gm per day). The low-calorie group achieved their fat goal of 30% of calorie intake, but they consumed from 300 to 700 kcal more than their calorie goal. Caloric intake, physical activity, palatability, satiety, quality of life, and weight loss were not significantly different by treatment. Two studies, which gave patients hypocaloric diets of varying fat and carbohydrate content (fat calories 10% to 45%) for from 10 to 12 weeks, found no effect of diet composition on weight loss. In addition, one study, which gave patients a low-fat, energy-unrestricted diet (fat calories 19%), reported a weight loss of 10.1 lb at 16 to 20 weeks and 5.7 lb at 9 to 12 months, which is similar to that seen in the low-fat group in the this study. Most of the decrease in fat intake (90%) in the low-fat group resulted from a reduction in intake of fat from fat and oils; meat, fish, and poultry; dairy products; and sweets. The dietary changes in the low-fat group are consistent with those found in one study, which prescribed a 15% fat calorie diet to women with breast cancer. Intake of vitamin C increased in the low-fat group and decreased in the low-calorie group. This difference was significant and was caused by an increased intake of fruits and vegetables in the low-fat group and a decreased consumption of fruits in the low-calorie group. Calcium intake decreased significantly more in the low-calorie group because of a decreased intake of dairy foods.     

Methods to increase fruit and vegetable intake with and without a decrease in fat intake: compliance and effects on body weight in the nutrition and breast health study

Dietary patterns that involve a decrease in fat and an increase in fruit and vegetable (FV) intake have been suggested to decrease cancer risks. In this study, intervention methods to selectively modify dietary fat and/or FV intakes were developed. Compliance to the diets and the effects on body weight are shown, because both of these dietary changes can impact on and be confounded by changes in energy intake. A total of 122 women with a family history of breast cancer were randomized onto one of four diets for 12 mo. Counseling methods were devised to increase amount and variety of FV consumed with or without a decrease in fat intake using modified exchange list diets. Women on the low-fat and combination low-fat/high-FV diet arms decreased their fat intakes to approximately 16% of energy. Women on the high-FV and the combination low-fat/high-FV diet arms increased FV intakes to approximately 11 servings/day. Despite counseling efforts to maintain baseline energy intakes, mean body weight increased significantly by 6 pounds in women in the high-FV diet arm and decreased significantly by 5 pounds in women in the low-fat diet arm. Percent body fat also was increased in the high-FV diet arm and decreased in the low-fat diet arm. Body weight and percent body fat in the combination diet arm did not change significantly. Control of energy intake, therefore, appears to have been achieved only when the addition of FV to the diet was balanced by a decrease in fat intake and both dietary components were enumerated daily. Maintenance of energy intake, therefore, did not appear to be attained intrinsically when individuals were counseled to make changes in the composition of their diets.     

Assessment of adherence to a low-fat diet for breast cancer prevention.

BACKGROUND. The relationships between self-reported adherence to a low-fat diet in healthy women between the ages of 44 and 69 and a number of correlates of this self-reported behavior were examined in an attempt to improve monitoring of adherence to nutritional intervention trials for breast cancer prevention. METHODS. Dietary fat intake in 87 women who completed 6 months of nutritional intervention was reduced from 38.2 +/- 5.9% to 21.7 +/- 7.8% of total energy intake (P less than 0.005). Reported total calorie intake was reduced by approximately 20%. RESULTS. Body weight decreased by 2.7% from 68.1 +/- 11.2 kg to 66.3 +/- 11.9 kg (P less than 0.05). Fasting total plasma cholesterol levels decreased from 205 +/- 31 mg/dl to 184 +/- 29 mg/dl (P less than 0.05). Fasting plasma triglyceride levels did not change significantly (97 +/- 44 mg/dl vs 101 +/- 55 mg/dl). Relative percentage changes in body weight correlated with percentage changes in dietary fat intake (r = 0.23, P less than 0.05). CONCLUSION. Self-reported changes in dietary behavior correlated significantly with objective changes in body weight and fasting cholesterol in these healthy women encouraged to consume a low-fat diet for prevention of breast cancer.     

Dietary energy density in the treatment of obesity: a year-long trial comparing 2 weight-loss diets

BACKGROUND: Consuming foods low in energy density (kcal/g) decreases energy intake over several days, but the effectiveness of this strategy for weight loss has not been tested. OBJECTIVE: The effects on weight loss of 2 strategies for reducing the energy density of the diet were compared over 1 y. DESIGN: Obese women (n = 97) were randomly assigned to groups counseled either to reduce their fat intake (RF group) or to reduce their fat intake and increase their intake of water-rich foods, particularly fruit and vegetables (RF+FV group). No goals for energy or fat intake were assigned; the subjects were instructed to eat ad libitum amounts of food while following the principles of their diet. RESULTS: After 1 y, study completers (n = 71) in both groups had significant decreases in body weight (P < 0.0001). Subjects in the RF+FV group, however, had a significantly different pattern of weight loss (P = 0.002) than did subjects in the RF group. After 1 y, the RF+FV group lost 7.9 +/- 0.9 kg and the RF group lost 6.4 +/- 0.9 kg. Analysis of all randomly assigned subjects also showed a different pattern of weight loss between groups (P = 0.021). Diet records indicated that both groups had similar reductions in fat intake. The RF+FV group, however, had a lower dietary energy density than did the RF group (P = 0.019) as the result of consuming a greater weight of food (P = 0.025), especially fruit and vegetables (P = 0.037). The RF+FV group also reported less hunger (P = 0.003). CONCLUSION: Reducing dietary energy density, particularly by combining increased fruit and vegetable intakes with decreased fat intake, is an effective strategy for managing body weight while controlling hunger.     

Association between dairy food consumption and weight change over 9 y in 19,352 perimenopausal women

BACKGROUND: Dairy foods may play a role in the regulation of body weight. OBJECTIVE: We examined the association between changes in dairy product consumption and weight change over 9 y. DESIGN: The study was conducted in 19 352 Swedish women aged 40-55 y at baseline. Data on dietary intake, body weight, height, age, education, and parity were collected in 1987-1990 and 1997. The intake frequencies of whole milk and sour milk (3% fat), medium-fat milk (1.5% fat), low-fat milk and sour milk (or=1 serving/d; 3) constant, >or=1 serving/d; and 4) decreased from >or=1 serving/d to <1 serving/d. Odds ratios (ORs) with 95% CIs for an average weight gain of >or=1 kg/y were calculated by using multivariable logistic regression analyses, with group 1 as the reference. RESULTS: Mean (+/-SD) body mass index (in kg/m2) at baseline was 23.7 +/- 3.5. The constant (>or=1 serving/d) intakes of whole milk and sour milk and of cheese were inversely associated with weight gain; ORs for group 3 were 0.85 (95% CI: 0.73, 0.99) and 0.70 (95% CI: 0.59, 0.84) respectively. No significant associations were seen for the other 3 intake groups. When stratified by BMI, the findings remained significant for cheese and, for normal-weight women only, for whole milk and sour milk. CONCLUSION: The association between the intake of dairy products and weight change differed according to type of dairy product and body mass status. The mechanism behind these findings warrants further investigation.     

Effects of low-fat and/or high-fruit-and-vegetable diets on plasma levels of 8-isoprostane-F2alpha in the Nutrition and Breast Health study

Dietary patterns that involve both a decrease in fat and an increase in fruit and vegetable (FV) intake may decrease cancer risks. In this study, a total of 122 premenopausal women with a family history of breast cancer were randomized into one of four diets for 12 mo: nonintervention, low-fat (15% of energy from fat), high-FV(9 servings/d), and combination low-fat/high-FV Fasting blood samples were obtained at baseline and after 3, 6, and 12 mo. Levels of 8-isoprostane-F2a in plasma were deter-mined by immunoassay kits. Statistical analyses indicated that levels of 8-isoprostane-F2a decreased significantly with time in the low-fat arm, which is the only intervention that resulted in weight loss; there were no significant changes in the other three diet arms. It is unlikely that this is due to changes in levels of blood lipids because there was little change overtime in plasma total cholesterol, high-density lipoprotein,low-density lipoprotein (LDL), or triglyceride levels in any diet arm, although mean LDL did decrease slightly in women who reduced fat intake after adjustment for change in body mass index (BMI). Levels of baseline 8-isoprostane-F2a were significantly higher in obese women than in overweight or normal weight women, and change in BMI was significantly correlated with change in 8-isoprostane-F2a levels. These results indicate that low-fat diets or high-FV diets are unlikely to affect plasma levels of 8-isoprostane-F2a in healthy,premenopausal women who do not lose weight during dietary change.     

Effect on body weight of replacing dietary fat with olestra for two or ten weeks in healthy men and women

OBJECTIVE: To examine in two separate studies the effects of replacing dietary fat with Olestra on body composition and weight change in healthy young men and women. METHODS: Ten healthy, lean young men participated in Study One that was a 22-day single blind, within-subject design. After a control diet (40% fat) for eight days Study One subjects received an Olestra-substituted diet (31% metabolizable fat) for 14 days. Study Two was a randomized parallel-arm clinical trial with 15 healthy, lean and overweight young women. These subjects were randomly assigned to receive a control diet (40% fat), an Olestra-containing diet (31% metabolizable fat) or a reduced-fat diet (31% fat) for 10 weeks. All foods were provided to the subjects, and energy intakes were not restricted. The primary endpoint in both studies was change from baseline in body weight. In Study Two, body composition was measured by dual energy x-ray absorptiometry. In both studies, food intake and nutrient compensation were assessed. RESULTS: In Study One fat substitution by Olestra resulted in a significant 1.7 kg weight loss from baseline. In Study Two, change in body weight and body fat from baseline were statistically significant in all groups, but the group with Olestra lost significantly more weight from baseline (-5.0 kg) than the other two groups. In Study One there was partial compensation for the decreased energy intake, while in Study Two, compensation was seen only for those on the reduced-fat diet. CONCLUSION: Replacement of 1/3 of dietary fat with Olestra in periods of up to 10 weeks results in weight loss in men and women.     

Effect of low-fat and/or low-energy diets on anthropometric measures in participants of the women's diet study

OBJECTIVE: To compare the effects of low-fat, low-energy and combination low-fat/low-energy intervention on changes in six anthropometric measures in Caucasian and African-American free-living women. METHODS: The effects of dietary counseling strategies for fat and/or energy reduction were examined on anthropometric measures in 86 pre-menopausal women, average BMI of 28 kg/m2, who participated in a 12-week intervention trial called the Women's Diet Study. The dietary goals were 15% of energy from fat and/or 25% reduction in energy intake, relative to reported baseline intake, using a 2 x 2 factorial design. Analysis of covariance models were constructed to evaluate changes in anthropometric measures over the 12 weeks of study. RESULTS: The biggest difference by race was in women who were relatively heavier at baseline, in which case African-American women lost significantly less weight but decreased their waist:hip ratio to a significantly greater extent than Caucasian women. With regard to the effects of diet arm, weight loss varied depending on baseline weight, and in women with higher baseline weights, the combination low-fat/low-energy diet resulted in the most weight loss (6.7 kg, p < 0.05). Decreases in the other anthropometric measures at week 12 were more uniform across diet arms and did not depend on baseline values. After controlling for previous weight history and race, the decreases in BMI, percent body fat and waist circumference after 12 weeks were statistically equivalent with the low-fat, low-energy or combination low-fat/low-energy diets. The relatively greater decreases in percent body fat and waist circumference with the combination diet versus the low-fat or low-energy diets were not statistically significant. CONCLUSION: The low-fat, low-energy and combination diets all resulted in similar and statistically significant decreases in BMI, percent body fat and waist circumference over 12 weeks of intervention. The extent of weight loss, however, varied depending on baseline weight, and the combination diet was the only intervention to result in significant weight loss for women who were heavier at baseline. This indicates that, although there may be an advantage for reducing dietary fat in initially heavier women, any of these counseling strategies could be effective for improving anthropometric predictors of health risks associated with overweight status. This is useful since flexibility in dietary choices may facilitate adherence to dietary counseling in some individuals.     

Changes of body fat mass determined by be-electrical impedance and by anthropometry: BMI method and skinfolds method in overweight and obese women after implementation of low energy diet

OBJECTIVE: To estimate the effect of a low energy diet on body fat mass measured by bioelectrical impedance (BIA) in overweight (BMI > or = 25 < 30) and obese women (BMI > or = 30). DESIGN: Randomised six weeks trial. METHODS: The studied group consisted of 86 women aged 20-67 attended the Outpatients Clinic of Metabolic Disorders. Dietary assessments were performed by 24-hour dietary recall. Body fat mass was measured by bioelectrical impedance method and by skinfolds thickness method. Percent body fat and fat free mass was estimated from equations based on BMI and skinfolds thickness. RESULTS: In overweight women after 6 weeks of dietary treatment mean intake of energy decreased from 10071 +/- 2678 kJ to 4560.6 +/- 1405.8 kJ, total fat intake from 88.7 +/- 33.9 g/d (33.4% of energy) to 38.8 +/- 19.9 g/d (31.1% of energy), protein intake from 89.5 +/- 36.5 g/d (14.8% of energy) to 50.7 +/- 16.9 g/d (19.0% of energy), carbohydrates intake from 312.7 +/- 106.6 g/d (51.8% of energy) to 134.5 +/- 53.7 g/d (50% of energy). In obese women mean intake of energy decreased from 10,376.3 +/- 2953.9 kJ to 4665.2 +/- 1380.7 kJ. The value of total energy, total fat and saturated fatty acids intake correlated with body weight, BMI and body fat. After dietary treatment the body weight decreased by 2.4 kg (3.3%) in overweight women and by 3.9 kg (4.1%) in obese women and percent of body fat decreased by 1.6% and 2.3%, respectively. Body fat mass determined by BIA method significantly correlated with skinfolds method by Siri, Schutte, Rathbun, Brozek, Keys-Brozek, and BMI method by Webster, Deurenberg. CONCLUSION: BIA method may be a helpful tool for the analysis of changes in total body composition occurring under obesity treatment.     

Dietary intake and changes in lipoprotein lipids in obese, postmenopausal women placed on an American Heart Association Step 1 diet

BACKGROUND: Dietary intake and changes in lipoprotein lipids in obese, postmenopausal women placed on an American Heart Association Step 1 diet. OBJECTIVE: The purpose of this study was to determine the specific dietary factors associated with the commonly observed decrease in HDL-C concentration in obese, postmenopausal women placed on a low-fat diet. DESIGN/SUBJECTS/INTERVENTION: Dietary intake, lipoprotein lipid concentrations, and body weight were measured before and after 10 weeks of instruction in the principles of the American Heart Association (AHA) Step 1 diet in 55 overweight and obese (body mass index=33+/-4 kg/m2), sedentary, postmenopausal women (mean age 59+/-5 years). RESULTS: The percent of energy obtained from total fat, monounsaturated, polyunsaturated, saturated fat, and dietary cholesterol decreased significantly after dietary intervention, while the polyunsaturated:saturated ratio and the percent of energy obtained from total carbohydrate, complex carbohydrate, and simple carbohydrate increased. On average, the women lost a small, but significant, amount of body weight (2%+/-3%, P<.0001). Adherence to the AHA diet reduced total cholesterol (-8%+/-8%), LDL-C (-6%+/-11%), and HDL-C (-16%+/-10%). The only dietary change that predicted decreases in HDL-C concentrations was the increase in the percent of energy from simple sugar (r=-0.32, P<.05). There were no relationships between changes in HDL-C and changes in percent of energy from fat (r=0.16), saturated fat (r=0.07), polyunsaturated fat (r=0.04), or monounsaturated fat (r=0.09). APPLICATIONS/CONCLUSIONS: In postmenopausal women, a dietary reduction in total fat, saturated fat, and cholesterol reduces body weight, total cholesterol, and LDL-C, but substitution of simple sugar for dietary fat may lead to a reduction in HDL-C. Further research is needed to determine which specific simple sugars are contributing to diet-induced reductions in HDL-C in older women placed on a low-fat diet.     

Diet intervention methods to reduce fat intake: nutrient and food group composition of self-selected low-fat diets

A multicentered pilot study was conducted to test an intervention protocol designed to reduce fat intake to 15% of energy intake. Eligible subjects were postmenopausal women with stage II breast cancer whose baseline fat intake was more than 30% of energy intake. The low-fat diet intervention protocol consisted of bi-weekly individual counseling sessions with emphasis on substitution of lower-fat foods for high-fat foods and maintenance of nutritional adequacy. Nutrient intakes were calculated from 4-day food records collected at baseline and after 3 months of diet intervention. Mean daily fat intake for the 17 patients on the low-fat diet dropped significantly from 38.4 +/- 4.3% of energy intake at baseline to 22.8 +/- 7.8% at 3 months (p less than .001). A 25% reduction in mean energy intake, from 1,840 +/- 419 kcal at baseline to 1,365 +/- 291 kcal at 3 months, was accompanied by significant increases in protein and carbohydrate as percent of energy intake. A mean weight loss of 2.8 kg and a 7.7% reduction in serum cholesterol were observed; both changes were significant at the p less than .01 level. Absolute intakes of zinc and magnesium were significantly reduced. However, mean intake on the low-fat diet for 14 vitamins and minerals, including zinc and magnesium, exceeded two-thirds of the 1989 Recommended Dietary Allowances (RDAs). When expressed as nutrient density (i.e., amount of nutrient per 1,000 kcal), increases were observed for all micronutrients. These results support the hypothesis that a nutritionally adequate low-fat diet can be successfully implemented in a highly motivated, free-living population.     

Responses of inflammatory markers to a low-fat, high-carbohydrate diet: effects of energy intake

BACKGROUND: Inflammation contributes to atherogenesis. Dietary fats may be proinflammatory. OBJECTIVE: The objective was to determine whether energy intake modulates the effects of low-fat, high-carbohydrate intakes on inflammatory markers. DESIGN: Twenty-two healthy postmenopausal women with a mean (+/-SD) age of 61 +/- 11 y, who were not receiving hormone replacement therapy, were fed eucaloric diets to reduce their fat intake from 35% to 15% of energy. Next, the women consumed a 15%-fat ad libitum diet under free-living conditions. Serum highly sensitive C-reactive protein, interleukin 6, HDL serum amyloid A, and adiponectin concentrations were measured at the end of the eucaloric and ad libitum low-fat, high-carbohydrate intakes. RESULTS: The eucaloric diet decreased adiponectin from 16.3 +/- 2.1 to 14.2 +/- 2.0 mg/L (P < 0.05) and increased triacylglycerol from 131 +/- 11 to 164 +/- 14 mg/dL (P < 0.01). The ad libitum low-fat diet caused 6 kg weight loss and decreased highly sensitive C-reactive protein from 4.3 +/- 0.6 to 2.5 +/- 0.5 mg/L (P < 0.01), decreased HDL serum amyloid A from 10.3 +/- 1.8 to 5.7 +/- 1.3 mg/L (P < 0.001), increased adiponectin from 14.2 +/- 2.0 to 16.3 +/- 1.7 mg/L (P < 0.05), and decreased triacylglycerol from 164 +/- 14 to 137 +/- 15 mg/dL (P < 0.05). CONCLUSION: During the eucaloric phase, the low-fat, high-carbohydrate diet exerted unfavorable effects on the inflammatory markers. In contrast, the ad libitum low-fat, high-carbohydrate intake caused weight loss and affected inflammatory markers favorably. Thus, the energy content of a low-fat, high-carbohydrate diet determines changes in inflammatory markers.     

Comparison of energy-restricted very low-carbohydrate and low-fat diets on weight loss and body composition in overweight men and women

OBJECTIVE: To compare the effects of isocaloric, energy-restricted very low-carbohydrate ketogenic (VLCK) and low-fat (LF) diets on weight loss, body composition, trunk fat mass, and resting energy expenditure (REE) in overweight/obese men and women. DESIGN: Randomized, balanced, two diet period clinical intervention study. Subjects were prescribed two energy-restricted (-500 kcal/day) diets: a VLCK diet with a goal to decrease carbohydrate levels below 10% of energy and induce ketosis and a LF diet with a goal similar to national recommendations (%carbohydrate:fat:protein = ~60:25:15%). SUBJECTS: 15 healthy, overweight/obese men (mean +/- s.e.m.: age 33.2 +/- 2.9 y, body mass 109.1 +/- 4.6 kg, body mass index 34.1 +/- 1.1 kg/m2) and 13 premenopausal women (age 34.0 +/- 2.4 y, body mass 76.3 +/- 3.6 kg, body mass index 29.6 +/- 1.1 kg/m2). MEASUREMENTS: Weight loss, body composition, trunk fat (by dual-energy X-ray absorptiometry), and resting energy expenditure (REE) were determined at baseline and after each diet intervention. Data were analyzed for between group differences considering the first diet phase only and within group differences considering the response to both diets within each person. RESULTS: Actual nutrient intakes from food records during the VLCK (%carbohydrate:fat:protein = ~9:63:28%) and the LF (~58:22:20%) were significantly different. Dietary energy was restricted, but was slightly higher during the VLCK (1855 kcal/day) compared to the LF (1562 kcal/day) diet for men. Both between and within group comparisons revealed a distinct advantage of a VLCK over a LF diet for weight loss, total fat loss, and trunk fat loss for men (despite significantly greater energy intake). The majority of women also responded more favorably to the VLCK diet, especially in terms of trunk fat loss. The greater reduction in trunk fat was not merely due to the greater total fat loss, because the ratio of trunk fat/total fat was also significantly reduced during the VLCK diet in men and women. Absolute REE (kcal/day) was decreased with both diets as expected, but REE expressed relative to body mass (kcal/kg), was better maintained on the VLCK diet for men only. Individual responses clearly show the majority of men and women experience greater weight and fat loss on a VLCK than a LF diet. CONCLUSION: This study shows a clear benefit of a VLCK over LF diet for short-term body weight and fat loss, especially in men. A preferential loss of fat in the trunk region with a VLCK diet is novel and potentially clinically significant but requires further validation. These data provide additional support for the concept of metabolic advantage with diets representing extremes in macronutrient distribution.     

Food groups as predictors for short-term weight changes in men and women of the EPIC-Potsdam cohort

This study examined the effect of food group intake on subsequent 2-y weight change. Food-frequency questionnaire-based food intake data of 17,369 nonsmoking subjects of the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam cohort were examined in their relation to a subsequent weight change. Dietary data, collected from 1994 to 1998, were grouped into 24 food groups. Weight change per year follow-up was the outcome of interest; large weight gain was defined as > or =2 kg; small weight gain as > or =1 kg to <2 kg; large weight loss as < or = -2 kg; small weight loss as < or = -1 kg to > -2 kg and weight maintenance as +/- 1 kg. For each food group, a separate polytomous logistic regression model with stable weight as the reference group was constructed, controlling for age, body mass index, previous weight change, and behavioral and lifestyle factors. Odds ratios (OR) and 95% confidence intervals (CI) estimated the increase in risk associated with each 100 g/d increment in food group intake. In women, consumption of high energy, high fat food groups significantly predicted large weight gain, e.g., fats (OR = 1.75; 95% CI, 1.01-3.06), sauces (OR = 2.12; 95% CI, 1.17-3.82) and meat (OR = 1.36; 95% CI, 1.04-1.79), and the consumption of cereals predicted large weight loss (OR = 1.43; 95% CI, 1.09-1.88). In men, intake of high energy, high sugar foods, i.e., sweets, was significantly predictive of large weight gain (OR = 1.48; 95% CI, 1.03-2.13). Our data show that a diet rich in high fat and high energy foods predicts short-term weight gain even if controlled for many potential confounding factors.     

Prospective, randomized, controlled comparison of the effects of low-fat and low-fat plus high-fiber diets on serum lipid concentrations.

Previous studies examining the hypocholesterolemic effects of high-soluble-fiber diets have not been designed to control for dietary fat intake. Serum cholesterol reductions may therefore be accounted for by differences in consumption of fat. Moderately hypercholesterolemic, nonobese, Caucasian men and women, 30-50 y old were randomly assigned to low-fat, low-fat plus high-fiber, or usual-diet groups and followed for 12 mo. At 12 mo the high-fiber group consumed significantly more soluble fiber than both the low-fat and usual-diet groups (P = 0.0063 and P = 0.0001); the high-fiber group did not differ from the low-fat group in quantity of dietary fat consumed. The high-fiber group experienced a greater average reduction (13%) in serum cholesterol than did the low-fat (9%) and usual-diet (7%) groups. After adjustment for relevant covariates, the reduction in the high-fiber group was significantly greater than that in the low-fat group (P = 0.0482). Supplementation with soluble fiber reduces serum cholesterol beyond the reduction observed with low-fat diet alone.     

Influence of caloric contribution and saturation of dietary fat on plasma lipids in premenopausal women

Total cholesterol, HDL cholesterol, and triglycerides were measured in 31 premenopausal women randomized into one of two diet groups: one diet with a P:S ratio of 1.0 and one diet with a P:S ratio of 0.3. Both groups were fed a high-fat diet (40% of energy from fat) for four menstrual cycles per subject followed by a similar interval on a low-fat diet (20% of energy from fat). Changing from the high-fat to the low-fat diet resulted in a nonsignificant mean decrease of 7% in total cholesterol. HDL-cholesterol response to the low-fat regimen was influenced by the P:S ratio. Women in the high P:S group showed no change; mean HDL cholesterol in women in the low P:S group decreased 12%. Plasma triglycerides increased in both groups on the low-fat diet although the increase was greatest in the low P:S group.     

Do beans and oat bran add to the effectiveness of a low-fat diet?

The effects of consuming an increased amount of soluble fibre as oat bran or beans were examined in 40 free-living hypercholesterolaemic men and women. The subjects were initially established on a low-fat background diet (29% of energy from fat) and then 55 g low-fibre oat bran, 55 g high-fibre oat bran or 80 g mixed cooked beans were added to their diet in random order for 6 week periods. Body weight and overall composition of the diet did not change. Plasma cholesterol and low-density lipoprotein cholesterol (LDL-C) were unchanged. High-density lipoprotein cholesterol (HDL-C) was significantly higher on all three intervention diets than on the lower fibre run-in diet. Supplementation of a moderately low-fat diet with palatable quantities of oat bran or beans without changing the overall fat intake does not appear to significantly lower cholesterol but may have a benefit by increasing HDL-C and reducing the ratio of LDL-C to HDL-C.     

Metabolic responses to high-fat or low-fat meals and association with sympathetic nervous system activity in healthy young men

The present study was designed to investigate the metabolic and sympathetic responses to a high-fat meal in humans. Fourteen young men (age: 23.6 +/- 0.5 y, BMI: 21.3 +/- 0.4 kg/m2) were examined for energy expenditure and fat oxidation measured by indirect calorimetry for 3.5 h after a high-fat (70%, energy from fat) or an isoenergetic low-fat (20% energy from fat) meal served in random order. The sympathetic nervous system (SNS) activity was assessed using power spectral analysis of heart rate variability (HRV). After the high-fat meal, increases in thermoregulatory SNS activity (very low-frequency component of HRV, 0.007-0.035 Hz, 577.4+/-45.9 vs. 432.0+/-49.3 ms2, p<0.05) and fat oxidation (21.0+/-5.3 vs. 13.3+/-4.3 g, p<0.001) were greater than those after the low-fat meal. However, thermic effects of the meal (TEM) were lower after the high-fat meal than after the low-fat meal (27.5+/-11.2 vs. 36.1+/-10.9 kcal, p<0.05). In conclusion, the high-fat meal can stimulate thermoregulatory SNS and lipolysis, but resulted in lower TEM, suggesting that a high proportion of dietary fat intake, even with a normal daily range of calories, may be a potent risk factor for further weight gain.     

Changes in food sources of dietary fat in response to an intensive low-fat dietary intervention: early results from the Women's Health Initiative

OBJECTIVE: To evaluate changes in food sources of dietary fat made by participants in the Women's Health Initiative Low-Fat Dietary Modification Trial. DESIGN: This study compares sources of dietary fat intake, estimated by a food frequency questionnaire, between intervention and control participants at baseline, 1 year (year 1) and 2 years (year 2) after randomization. The outcome measure was intake of fat in grams per day. Results are given on consumption of fat from six food groups and the intervention effect, defined as mean change in the intervention group minus the change in controls, controlling for baseline fat intake. PARTICIPANTS: 5,004 intervention and 7,426 control postmenopausal women in 40 clinical centers across the United States. RESULTS: At baseline, the major sources of fat were added fats, such as butter, oils, and salad dressings (25%); meats (21%); and desserts (13%). From baseline to year 1, the intervention group reduced fat by 24.3 g/day compared with the control group. Reductions came primarily from added fats (9.1 g/day), meats (4.6 g/day), and desserts (3.9 g/day). White people reduced added fats more than other race/ethnicity groups did, white and Hispanic people were more likely to reduce fat intake from milk and cheese compared with other groups, and Hispanics reduced fat from mixed dishes more than did other race/ethnicity groups (P<.05 for all). APPLICATIONS/CONCLUSIONS: These data indicate that women in the Women's Health Initiative dietary change intervention made substantial changes in food choices. These results can facilitate future low-fat interventions, and also offer clinical applications, by identifying foods that may be refractory to change.