Effects of a Low-Fat Vegan Diet on Gut Microbiota in Overweight Individuals and Relationships with Body Weight, Body Composition, and Insulin Sensitivity. A Randomized Clinical Trial

Diet modulates gut microbiota and plays an important role in human health. The aim of this study was to test the effect of a low-fat vegan diet on gut microbiota and its association with weight, body composition, and insulin resistance in overweight men and women. We enrolled 168 participants and randomly assigned them to a vegan (n = 84) or a control group (n = 84) for 16 weeks. Of these, 115 returned all gut microbiome samples. Gut microbiota composition was assessed using uBiome Explorer™ kits. Body composition was measured using dual energy X-ray absorptiometry. Insulin sensitivity was quantified with the predicted clamp-derived insulin sensitivity index from a standard meal test. Repeated measure ANOVA was used for statistical analysis. Body weight decreased in the vegan group (treatment effect −5.9 kg [95% CI, −7.0 to −4.9 kg]; p < 0.001), mainly due to a reduction in fat mass (−3.9 kg [95% CI, −4.6 to −3.1 kg]; p < 0.001) and in visceral fat (−240 cm3 [95% CI, −345 to −135 kg]; p < 0.001). PREDIcted M, insulin sensitivity index (PREDIM) increased in the vegan group (treatment effect +0.83 [95% CI, +0.48 to +1.2]; p < 0.001). The relative abundance of Faecalibacterium prausnitzii increased in the vegan group (+5.1% [95% CI, +2.4 to +7.9%]; p < 0.001) and correlated negatively with changes in weight (r = −0.24; p = 0.01), fat mass (r = −0.22; p = 0.02), and visceral fat (r = −0.20; p = 0.03). The relative abundance of Bacteroides fragilis decreased in both groups, but less in the vegan group, making the treatment effect positive (+18.9% [95% CI, +14.2 to +23.7%]; p < 0.001), which correlated negatively with changes in weight (r = −0.44; p < 0.001), fat mass (r = −0.43; p < 0.001), and visceral fat (r = −0.28; p = 0.003) and positively with PREDIM (r = 0.36; p < 0.001), so a smaller reduction in Bacteroides fragilis was associated with a greater loss of body weight, fat mass, visceral fat, and a greater increase in insulin sensitivity. A low-fat vegan diet induced significant changes in gut microbiota, which were related to changes in weight, body composition, and insulin sensitivity in overweight adults, suggesting a potential use in clinical practice.

Download Full-text

A Plant-Based High-Carbohydrate, Low-Fat Diet in Overweight Individuals in a 16-Week Randomized Clinical Trial: The Role of Carbohydrates

Nutrients ◽

10.3390/nu10091302 ◽

2018 ◽

Vol 10 (9) ◽

pp. 1302 ◽

Cited By ~ 14

Author(s):

Hana Kahleova ◽

Sara Dort ◽

Richard Holubkov ◽

Neal Barnard

Keyword(s):

Insulin Resistance ◽

Body Composition ◽

Fat Mass ◽

Treatment Effect ◽

Group Treatment ◽

Low Fat ◽

High Carbohydrate ◽

Low Fat Diet ◽

Vegan Group

The effects of carbohydrates on body weight and insulin sensitivity are controversial. In this 16-week randomized clinical trial, we tested the role of a low-fat, plant-based diet on body weight, body composition and insulin resistance. As a part of this trial, we investigated the role of changes in carbohydrate intake on body composition and insulin resistance. Participants (n = 75) were randomized to follow a plant-based high-carbohydrate, low-fat (vegan) diet (n = 38) or to maintain their current diet (n = 37). Dual-energy X-ray absorptiometry was used to measure body composition. Insulin resistance was assessed with the Homeostasis Model Assessment (HOMA-IR) index. A repeated measure ANOVA model was used to test the between-group differences from baseline to 16 weeks. A linear regression model was used to test the relationship between carbohydrate intake, and body composition and insulin resistance. Weight decreased significantly in the vegan group (treatment effect −6.5 [95% CI −8.9 to −4.1] kg; Gxt, p < 0.001). Fat mass was reduced in the vegan group (treatment effect −4.3 [95% CI −5.4 to −3.2] kg; Gxt, p < 0.001). HOMA-IR was reduced significantly in the vegan group (treatment effect −1.0 [95% CI −1.2 to −0.8]; Gxt, p = 0.004). Changes in consumption of carbohydrate, as a percentage of energy, correlated negatively with changes in BMI (r = −0.53, p < 0.001), fat mass (r = −0.55, p < 0.001), volume of visceral fat (r = −0.35, p = 0.006), and HOMA (r = −0.27, p = 0.04). These associations remained significant after adjustment for energy intake. Changes in consumption of total and insoluble fiber correlated negatively with changes in BMI (r = −0.43, p < 0.001; and r = −0.46, p < 0.001, respectively), fat mass (r = −0.42, p < 0.001; and r = −0.46, p < 0.001, respectively), and volume of visceral fat (r = −0.29, p = 0.03; and r = −0.32, p = 0.01, respectively). The associations between total and insoluble fiber and changes in BMI and fat mass remained significant even after adjustment for energy intake. Increased carbohydrate and fiber intake, as part of a plant-based high-carbohydrate, low-fat diet, are associated with beneficial effects on weight, body composition, and insulin resistance.

Download Full-text

Gut Microbiota Manipulation in Mice Fed High or Low Glycemic Diets Affects Metabolic and Eye Health (P20-042-19)

Current Developments in Nutrition ◽

10.1093/cdn/nzz040.p20-042-19 ◽

2019 ◽

Vol 3 (Supplement_1) ◽

Author(s):

Kelsey Smith ◽

Sarah Francisco ◽

Ying Zhu ◽

Kathryn Barger ◽

Donald E Smith ◽

...

Keyword(s):

Body Composition ◽

Body Weight ◽

Insulin Sensitivity ◽

Gut Microbiota ◽

Health Outcomes ◽

Control Group ◽

Retinal Damage ◽

Metabolome Analysis ◽

Eye Health ◽

Significant Difference

Abstract Objectives We sought to identify the role of gut microbiota in the previously discovered relationship between a high glycemic diet and the development of retinal damage and metabolic health outcomes in aged mice. Methods Male C57Bl6/J mice aged 12 months were fed equal amounts of a high glycemic (HG) or low glycemic (LG) diet for 12 months. The compositions of the diets were identical apart from the starch, which was 100% amylopectin in the HG diet and 30% amylopectin/70% amylose in the LG diet. Within each diet, mice were assigned to one of three treatment conditions: antibiotic ablation of gut microbiota (HGabx or LGabx), weekly fecal microbiota transplants (FMT) from donor control mice fed the alternate diet (HG[tLG] or LG[tHG]), or a control group. Mice were weighed weekly and feces and urine were collected at regular intervals for microbiome and metabolome analysis respectively. Mice underwent MRIs to determine body composition, intraperitoneal glucose tolerance tests to determine glycemic responses, and eye fundus imaging and fluorescein angiography to evaluate the health of the retina and retinal vasculature. Results Compared with LG-fed controls, the HG-fed controls had significantly increased body fat mass, decreased insulin sensitivity, and an increased prevalence of retinal damage including hypopigmentation and vascular tortuosity. There was no significant difference in body weight between the HGabx and LGabx group throughout the study. The LGabx group had a significantly higher body weight and the HGAbx had significantly lower body weight than their respective control groups throughout the study. The LGabx group had the highest prevalence of abnormal retinal findings. Survival was significantly decreased in the HGabx mice compared with mice of all other groups of mice, and most died suddenly and presented with an enlarged and hemorrhagic cecum. There was no significant effect of the FMT on body weight or body composition compared with the control mice. The HG[tLG] group had improved insulin sensitivity relative to the HG controls. Conclusions Gut microbiota mediate the relationship between the glycemic response to the diet and health outcomes such as obesity, insulin sensitivity, eye health, and survival. Funding Sources BrightFocus Foundation, USDA/NIFA AFRI grant 2015-05470, USDA contract 1950-510000-060-03A from ARS, Stanley N. Gershoff Scholarship.

Download Full-text

A Six-Month Randomized Controlled Trial of Whole Soy and Isoflavones Daidzein on Body Composition in Equol-Producing Postmenopausal Women with Prehypertension

Journal of Obesity ◽

10.1155/2013/359763 ◽

2013 ◽

Vol 2013 ◽

pp. 1-9 ◽

Cited By ~ 11

Author(s):

Zhao-min Liu ◽

Suzanne C. Ho ◽

Yu-ming Chen ◽

Jean Woo

Keyword(s):

Body Composition ◽

Body Weight ◽

Postmenopausal Women ◽

Fat Mass ◽

Controlled Trial ◽

Milk Powder ◽

Soy Flour ◽

Low Fat ◽

Double Blind ◽

Good Compliance

Objectives. This paper reported the effects of commonly used whole soy foods (soy flour) and purified daidzein (one of the major isoflavones and the precursor of equol) on changes in anthropometric measurements and body composition in a 6-month double-blind, randomized, placebo-controlled trial among prehypertensive postmenopausal women who are also equol producers.Methods. 270 eligible women were randomized to either one of the three treatments: 40 g soy flour (whole soy group), 40 g low-fat milk powder + 63 mg daidzein (daidzein group), or 40 g low-fat milk powder (placebo group) daily each for 6 months. Anthropometric indicators and body composition were measured before and after intervention.Results. 253 subjects completed the study with good compliance. Urinary isoflavones levels suggested good compliance of subjects with supplementation. Whole soy and purified daidzein had no significant effect on body weight, body mass index (BMI), waist and hip circumferences, waist to hip ratio (WHR), body fat percentage, fat mass, and free fat mass. Conclusion. Six-month consumption of whole soy and purified daidzein at provided dosage had no improvement on body weight and composition compared with isocaloric milk placebo among prehypertensive equol-producing postmenopausal women. This trial is registered with ClinicalTrials.govNCT01270737.

Download Full-text

Assessing the utility of cardiorespiratory fitness, visceral fat, and liver fat in predicting changes in insulin sensitivity beyond simple changes in body weight after exercise training in adolescents

Applied Physiology Nutrition and Metabolism ◽

10.1139/apnm-2020-0284 ◽

2021 ◽

Vol 46 (1) ◽

pp. 55-62

Author(s):

Jennifer L. Kuk ◽

SoJung Lee

Keyword(s):

Body Composition ◽

Body Weight ◽

Insulin Sensitivity ◽

Exercise Training ◽

Glucose Tolerance ◽

Weight Change ◽

Visceral Fat ◽

Liver Fat ◽

Body Weight Change ◽

Sensitivity Changes

To examine the utility of changes in cardiorespiratory fitness (CRF) and body composition in response to exercise training in adolescents with obesity beyond simple measures of body weight change. This is a secondary analysis of our previously published randomized trials of aerobic, resistance, and combined training. We included 104 adolescents (body mass index (BMI) ≥85th percentile) who had complete baseline and post-intervention data for CRF, regional body fat, insulin sensitivity, and oral glucose tolerance. Associations between changes in body composition and CRF with cardiometabolic variables were examined adjusted for age, sex, Tanner stage, race, exercise group, and weight loss. At baseline, CRF, visceral fat and liver fat were correlated with insulin sensitivity with and without adjustment for BMI percentile. Training-associated changes in CRF, visceral fat, and liver fat were also correlated with insulin sensitivity changes, but not independent of body weight change. After accounting for body weight change, none of the body composition or CRF were associated with changes in insulin sensitivity, glucose tolerance, systolic blood pressure, or high-density lipoprotein cholesterol. Although CRF and body composition were strong independent correlates of insulin sensitivity at baseline, changes in CRF and visceral fat were not associated with changes in insulin sensitivity after accounting for body weight change. Clinicaltrials.gov registration nos.: NCT00739180, NCT01323088, NCT01938950. Novelty With exercise training, changes in body weight, CRF, visceral fat, and liver fat were correlated with changes in insulin sensitivity. Changes in body composition or CRF generally did not remain significant correlates of changes in insulin sensitivity after adjusting for body weight changes.

Download Full-text

OR26-06 Fecal Microbiota Transplantation Trial for the Improvement of Metabolism (FMT-TRIM): A Randomized Double-Blind Placebo-Controlled Pilot Trial

Journal of the Endocrine Society ◽

10.1210/jendso/bvaa046.995 ◽

2020 ◽

Vol 4 (Supplement_1) ◽

Author(s):

Elaine Wei-Yin Yu ◽

Gao Liu ◽

Petr Stastka ◽

Michael Chadwick Cheney ◽

Jasmin Mahabamunuge ◽

...

Keyword(s):

Body Composition ◽

Body Weight ◽

Insulin Sensitivity ◽

Gut Microbiota ◽

Fecal Microbiota Transplantation ◽

Pilot Trial ◽

Fecal Microbiota ◽

Obese Adults ◽

Double Blind ◽

Microbiome Diversity

Abstract Background: There is intense interest about the therapeutic potential of altering gut microbiota to improve metabolism, based primarily on intriguing animal studies. One prior trial of fecal microbiota transplantation (FMT) in obese men found that improved metabolic response after FMT was predicted by low baseline microbiome diversity. In the current trial, we investigated the safety and efficacy of weekly oral FMT capsules to improve glycemic outcomes in obese adults, and also explored determinants of successful microbiome engraftment and metabolic improvement after FMT. Methods: FMT-TRIM was a double-blind randomized placebo-controlled pilot trial of weekly oral FMT vs placebo capsules for 6 weeks in 24 obese adults with mild-moderate insulin resistance. Each participant in the FMT arm received capsules derived from one of 4 metabolically healthy lean donors (BMI 18.5-23 kg/m2). The primary outcome was change in insulin sensitivity assessed by hyperinsulinemic euglycemic clamp at 0 and 6 weeks. Secondary outcomes included body weight, metabolic labs, and body composition assessed by DXA over 12 weeks. 16SV4 rRNA sequencing was performed to assess microbiome composition and engraftment. Post-hoc exploratory analyses investigated metabolic outcomes after stratification by baseline microbiome diversity. Results: FMT and placebo groups were well balanced in terms of age (mean±SD 40±9 yrs), BMI (40±6 kg/m2), sex (72% female), and baseline metabolic measures. During the study, there were no statistically significant differences in insulin sensitivity between the FMT and placebo groups (+5 ± 12% FMT vs -3 ± 32% placebo, mean percent difference 9%, 95% CI -5% to 28%; p=0.16). There was a minor improvement in HbA1c at 12 weeks after FMT as compared to placebo (mean difference -0.1, 95% CI -0.3-0.01), but no significant differences in other metabolic labs, body weight, or body composition. Microbial engraftment varied by donor but was present in most FMT recipients, with persistence of engrafting strains throughout the 12-week study. Subgroup analyses of subjects with low microbiome diversity at baseline (FMT n=4, placebo n=7) showed a relative benefit of FMT over placebo at 12 weeks for HbA1c (mean difference -0.2, 95% CI -0.4 to -0.01), total cholesterol (-22 mg/dL, 95% CI -40 to -4 mg/dL), and fasting glucose (-10 mg/dL, 95% CI -19 to -1 mg/dL). There were no significant differences in adverse events between FMT and placebo groups. Conclusion: Weekly administration of FMT capsules results in gut microbiota engraftment for at least 12 weeks but does not meaningfully alter human metabolism in an unselected population of obese adults. Future studies are needed to elucidate the role of baseline recipient microbial diversity and other factors on the impact of FMT.

Download Full-text

Fat Quantity and Quality, as Part of a Low-Fat, Vegan Diet, Are Associated with Changes in Body Composition, Insulin Resistance, and Insulin Secretion. A 16-Week Randomized Controlled Trial

Nutrients ◽

10.3390/nu11030615 ◽

2019 ◽

Vol 11 (3) ◽

pp. 615 ◽

Cited By ~ 7

Author(s):

Hana Kahleova ◽

Adela Hlozkova ◽

Rebecca Fleeman ◽

Katie Fletcher ◽

Richard Holubkov ◽

...

Keyword(s):

Insulin Resistance ◽

Fatty Acids ◽

Body Composition ◽

Insulin Secretion ◽

Energy Intake ◽

Fat Mass ◽

Vegan Diet ◽

Model Assessment ◽

Fat Intake ◽

Low Fat

Macronutrient composition of the diet influences the development of obesity and insulin resistance. The aim of this study was to assess the role of dietary fat quantity and fatty acid composition in body composition, insulin resistance, and insulin secretion. An open parallel randomized trial design was used. Overweight participants (n = 75) were randomized to follow a low-fat vegan (n = 38) or control diet (n = 37) for 16 weeks. Dual X-ray absorptiometry was used to measure body composition. Insulin resistance was assessed with the Homeostasis Model Assessment (HOMA-IR) index. Insulin secretion was assessed after stimulation with a liquid breakfast (Boost Plus, Nestle, Vevey, Switzerland). Self-reported 3-day diet records were used to assess dietary intake. A linear regression model was used to test the relationship between fat intake and body composition, insulin resistance, and insulin secretion. Changes in fat intake expressed as percent of total energy consumed correlated positively with changes in fat mass (r = 0.52; p < 0.001; and 0.347; p = 0.006, respectively), even after adjustment for changes in body-mass index (BMI) and energy intake (0.33; p = 0.01). Decreased intakes of C18:0 (r = 0.37, p = 0.004) and CLA-trans-10-cis12 (r = 0.40, p = 0.002), but increased intake of C18:2 (r = −0.40, p = 0.002) and C18:3 (p = −0.36, p = 0.006), were associated with a decrease in HOMA-IR, independent on changes in BMI and energy intake. The main fatty acids associated with changes in fasting insulin secretion were C12:0 (r = −0.31, p = 0.03), and TRANS 16:1 (r = −0.33, p = 0.02), both independent on changes in BMI and energy intake. Our findings demonstrate that, in the context of a low-fat vegan diet, decreased intake of saturated and trans fats and increased relative content of polyunsaturated fatty acids, particularly linoleic and α-linolenic acids, are associated with decreased fat mass and insulin resistance, and enhanced insulin secretion.

Download Full-text

Effect of a Low-Fat Vegan Diet on Body Weight, Insulin Sensitivity, Postprandial Metabolism, and Intramyocellular and Hepatocellular Lipid Levels in Overweight Adults

JAMA Network Open ◽

10.1001/jamanetworkopen.2020.25454 ◽

2020 ◽

Vol 3 (11) ◽

pp. e2025454 ◽

Cited By ~ 2

Author(s):

Hana Kahleova ◽

Kitt Falk Petersen ◽

Gerald I. Shulman ◽

Jihad Alwarith ◽

Emilie Rembert ◽

...

Keyword(s):

Body Weight ◽

Insulin Sensitivity ◽

Vegan Diet ◽

Lipid Levels ◽

Low Fat ◽

Postprandial Metabolism ◽

Overweight Adults

Download Full-text

GH effect on enzyme activity of 11βHSD in abdominal obesity is dependent on treatment duration

Acta Endocrinologica ◽

10.1530/eje.1.02061 ◽

2006 ◽

Vol 154 (1) ◽

pp. 69-74 ◽

Cited By ~ 9

Author(s):

Helga Á Sigurjónsdóttir ◽

Josef Koranyi ◽

Magnus Axelson ◽

Bengt-Åke Bengtsson ◽

Gudmundur Johannsson

Keyword(s):

Insulin Sensitivity ◽

Abdominal Obesity ◽

Fat Mass ◽

Visceral Fat ◽

Controlled Trial ◽

Metabolic Effects ◽

Glucose Disposal ◽

Gh Treatment ◽

Double Blind

Objective: In the past years the interaction of GH and 11βhydroxysteroid dehydrogenase (11βHSD) in the pathogenesis of central obesity has been suggested. Design: We studied the effects of 9 months of GH treatment on 11βHSD activity and its relationship with body composition and insulin sensitivity in 30 men with abdominal obesity, aged 48–66 years, in a randomised, double-blind, placebo-controlled trial. Methods: Urinary steroid profile was used to estimate 11βHSD type 1 and 2 (11βHSD1 and 11βHSD2) activities. Abdominal s.c. and visceral adipose tissues were measured using computed tomography. Glucose disposal rate (GDR) obtained during a euglycaemic–hyperinsulinaemic glucose clamp was used to assess insulin sensitivity. Results: In the GH-treated group the 11βHSD1 activity decreased transiently after 6 weeks (P < 0.01) whereas 11βHSD2 increased after 9 months of treatment (P < 0.05). Between 6 weeks and 9 months, GDR increased and visceral fat mass decreased. Changes in 11βHSD1 correlated with changes in visceral fat mass between baseline and 6 weeks. There were no significant correlations between 11βHSD1 and 11βHSD 2 and changes in GDR. Discussion: The study demonstrates that short- and long-term GH treatment has different effects on 11βHSD1 and 11βHSD2 activity. Moreover, the data do not support that long-term metabolic effects of GH are mediated through its action on 11βHSD.

Download Full-text

Dissecting the Role of the Gut Microbiota and Diet on Visceral Fat Mass Accumulation (OR31-07-19)

Current Developments in Nutrition ◽

10.1093/cdn/nzz037.or31-07-19 ◽

2019 ◽

Vol 3 (Supplement_1) ◽

Author(s):

Caroline Le Roy ◽

Ruth Bowyer ◽

Claire Steves ◽

Tim Spector ◽

Bell Jordana

Keyword(s):

Vitamin E ◽

Random Forest ◽

Gut Microbiota ◽

Fat Mass ◽

Mediation Analysis ◽

Visceral Fat ◽

Nutrient Intake ◽

Microbiota Composition ◽

Gut Microbiota Composition

Abstract Objectives Accumulation of visceral fat mass (VFM) is a major risk factor for cardiovascular and metabolic disease. Both gut microbiota and diet have been shown to impact host adiposity in an interdependent manner, but the exact nature of their joint contributions has not been characterised. Here, we aimed to estimate and separate the effect of gut microbiota composition from that of nutrient intake on host VFM in of 1760 older female twins. Methods The gut microbiome profile was assessed by 16S sequencing. VFM was measured by DEXA whole body scan and nutrient intake was assessed through food frequency questionnaires. We used a combination of pair-wise associations, random forest modelling and mediation analysis to separate the effect of the gut microbiota and nutrients on VFM. Results Pairwise analyses revealed that 93 OTUs and 10 nutrients were significantly linked to VFM. Five of the 10 nutrients (fibre, trans fatty acids, magnesium, vitamin E and biotin) were also associated with 23% of the 93 VFM-associated OTUs. To separate the effects of the gut microbiota from nutrients on VFM we carried out conditional analyses. We observed that the majority (87%) of the 93 OTUs remained significantly associated with VFM irrespective of nutrient intake correction. In contrast, we observed that fibre, magnesium, biotin and vitamin E were no longer significantly associated with VFM when adjusting models for OTUs (P > 0.05), implying a role of the gut microbiota in mediating these nutrient effects on VFM. Formal mediation analysis revealed that the individual effect of fibre, biotin, magnesium and vitamin E on VFM were mediated at 69, 43, 41 and 31% respectively by OTUs. Moreover, we estimated that accumulated effect of OTUs on VFM (R2 = 0.19) was twice the one of nutrients (R2 = 0.11) and so were their prediction potential determined using random forest classification. Conclusions Our results suggest that while the role of certain nutrients on VFM appears to depend on gut microbiota composition, specific gut microbes may affect host adiposity regardless of dietary intake. The findings imply that the gut microbiota may have a greater contribution towards shaping host adiposity and VFM, compared to diet alone. Funding Sources We gratefully acknowledge support provided by the JPI HDHL funded DINAMIC consortium (administered by the MRC UK, MR/N030125/1). Supporting Tables, Images and/or Graphs

Download Full-text

Effects of Ad Libitum Low Carbohydrate Versus Low Fat Diets on Body Weight and Fat Mass

Current Developments in Nutrition ◽

10.1093/cdn/nzaa049_051 ◽

2020 ◽

Vol 4 (Supplement_2) ◽

pp. 658-658

Author(s):

Alex Schick ◽

James Boring ◽

Amber Courville ◽

Isabelle Gallagher ◽

Juen Guo ◽

...

Keyword(s):

Weight Loss ◽

Body Weight ◽

Body Fat ◽

Fat Mass ◽

Kidney Diseases ◽

Primary Study ◽

Low Fat ◽

Fat Loss ◽

Low Carbohydrate ◽

Ad Libitum

Abstract Objectives To describe the effects of ad libitum low-fat (LF) and low-carbohydrate (LC) diets on body weight and fat mass. Methods Sixteen adults without diabetes spent 29 continuous days residing at the Metabolic Clinical Research Unit of the NIH Clinical Center where they were fed ad libitum either an animal-based, LC diet (75% fat, 10% carbohydrates, 15% protein) or a plant-based, LF diet (75% carbohydrates, 10% fat, 15% protein). Participants were randomly assigned to one diet for the first phase of the study (14 days), after which they were switched to the other diet for the remainder of the study. Participants were given three meals daily and were provided with additional snacks amounting to 200% of their daily energy requirements as determined by their resting energy expenditure multiplied by 1.6. Subjects were told that this was not a weight loss study and were not informed about the primary study aim. They were instructed to eat as much or as little as they desired. Total body weight and fat mass were measured using a calibrated scale and dual-energy X-ray absorptiometry, respectively. Subjects were blinded to their data and wore loose-fitting scrubs to avoid any feedback regarding changes in the fit of their clothing. Results Subjects included 7 women and 9 men, with an age of (mean ± SE) 29 ± 1.7 years and BMI of 27.5 ± 1.5 at baseline. Participants lost weight on both diets, with the LC diet resulting in 1.34 ± 0.31 kg of weight loss (P = 0.0006) and the LF diet resulting in 1.09 ± 0.31 kg of weight loss (P = 0.003) which was not significantly different from the LC diet (P = 0.58). However, participants lost 0.6 ± 0.17 kg of body fat on the LF diet (P = 0.002) but the LC diet did not result in significant body fat loss (0.04 ± 0.17 kg; P = 0.8) and the difference in body fat loss between the diets was statistically significant (P = 0.03). Conclusions While participants lost similar amounts of weight on both diets, only the LF diet led to significant body fat loss. Early weight loss with a LC diet does not necessarily reflect a similar state of negative energy balance as compared with a LF diet. Funding Sources Intramural Research Program of the National Institutes of Diabetes and Digestive and Kidney Diseases.

Download Full-text