Endothelial function and weight loss: Comparison of low-carbohydrate and low-fat diets

Currently, obesity treatment rests on the "calories-in, calories-out" (CICO) rule, formally named the energy balance theory (EBT). It maintains that body weight (BW) increases as food calories are greater than expended calories but decreases when the opposite occurs; hence, weight stability is expected at energy balance meaning that over time energy-in equals energy-out. It follows that dietary regimens with identical energy content should evoke similar amounts of weight and fat loss with only minor differences that follow from diet's macronutrient composition, e.g., diet-induced glycogen depletion and water excretion. A vast collection of evidence shows, however, that low-carbohydrate diets typically result in much greater weight and fat loss than isocaloric low-fat diets. Furthermore, our recent mathematical analysis demonstrated that weight stability coincides with a persistent energy imbalance and not otherwise. As an alternative, the mass balance model (MBM) was proposed that fitted weight loss data and explained the often superior weight loss evoked by low-carbohydrate diets versus low-fat diets. Here, we expand on these observations by computationally contrasting the predictions of both models in two scenarios described in the literature: altering the diet's macronutrient composition while energy intake is kept at weight maintenance level; and the weight loss response as diet composition is changed under untreated type 1 diabetes. Our results indicate that MBM predictions are remarkably accurate while those of the EBT are clearly erroneous. These findings may represent the beginning of a paradigm shift in obesity research.

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An assessment of low carbohydrate or low fat diets for weight loss at two year’s follow-up

Diabetic Medicine ◽

10.1111/j.1464-5491.2009.02926.x ◽

2009 ◽

Cited By ~ 1

Author(s):

PA Dyson ◽

S Beatty ◽

DR Matthews

Keyword(s):

Weight Loss ◽

Low Fat ◽

Low Carbohydrate ◽

Fat Diets

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Differential effects of low-carbohydrate and low-fat diets on inflammation and endothelial function in diabetes

Journal of Diabetes and its Complications ◽

10.1016/j.jdiacomp.2011.08.001 ◽

2011 ◽

Vol 25 (6) ◽

pp. 371-376 ◽

Cited By ~ 22

Author(s):

Nichola J. Davis ◽

Jill P. Crandall ◽

Srikanth Gajavelli ◽

Joan W. Berman ◽

Nora Tomuta ◽

...

Keyword(s):

Endothelial Function ◽

Low Fat ◽

Differential Effects ◽

Low Carbohydrate ◽

Fat Diets

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Reduced leptin and resistin and increased adiponectin are associated with improved endothelial function during weight loss with low fat compared to low carbohydrate diets

The FASEB Journal ◽

10.1096/fasebj.24.1_supplement.978.3 ◽

2010 ◽

Vol 24 (S1) ◽

Author(s):

Shane A. Phillips ◽

Jing‐Tan Bian ◽

Surabhi Bhutani ◽

Krista A. Varady

Keyword(s):

Weight Loss ◽

Endothelial Function ◽

Low Fat ◽

Low Carbohydrate

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Abstract MP63: Randomized Trials of Low-Fat vs. Other Diet Interventions on Weight Loss: A Meta-Analysis

Circulation ◽

10.1161/circ.129.suppl_1.mp63 ◽

2014 ◽

Vol 129 (suppl_1) ◽

Author(s):

Deirdre K Tobias ◽

Mu Chen ◽

Walter Willett ◽

Frank B Hu

Keyword(s):

Weight Loss ◽

Randomized Trials ◽

Dietary Intervention ◽

Meta Analysis ◽

Dietary Interventions ◽

Low Fat ◽

Intervention Intensity ◽

Low Carbohydrate ◽

Fat Diets

Introduction: The effectiveness of low-fat diets for weight loss has been debated for decades. Dozens of randomized control trials (RCTs) have assessed whether decreasing the intake of total fat leads to weight loss, giving mixed results. Hypothesis: We hypothesized that low-fat dietary interventions do not lead to greater weight loss when comparator diet intervention intensity is considered. Methods: We conducted a systematic review and meta-analysis. RCTs were included if they compared a low-fat dietary intervention to any control diet with at least 1 year of follow-up. We estimated the combined fixed effect inverse variance weighted mean difference of low-fat vs. comparison diets. Several a priori stratified analyses were considered to explore heterogeneity. Results: Fifty studies met inclusion criteria, reporting 1-10 years of follow-up on 70,054 participants. Overall, low-fat dietary interventions resulted in 0.51kg greater weight loss compared to other diets (95% CI = -0.62, -0.40, p<0.001; I2 = 83%). However, when trials where greater attention was given to the low-fat group were excluded, comparator diets led to greater weight loss than low-fat diets (n=30; WMD=0.87, 95% CI=0.56, 1.17, p<0.001). Similarly, when the type of comparator diet was considered, low-fat diets were only beneficial compared to control groups who were simply asked to maintain their usual diet (n=18; WMD = -1.03, 95% CI = -1.18, -0.88, p<0.001). When equal attention was given to intervention groups, low-carbohydrate diets (n=15; WMD = 1.13kg, 95% CI = 0.53, 1.73, p<0.001) and other “healthy” diets without a low-fat component (n=20; WMD = 0.77kg, 95% CI = 0.42, 1.13, p<0.001) led to greater weight loss than low-fat diets. Comparison diets, irrespective of type, were associated with 1.30kg greater weight loss than low-fat diets when the interventions were intended to be isocaloric (n=19; 95% CI = 0.92, 1.69, p<0.001). Conclusions: Low-fat dietary interventions are not more effective than other diets for weight loss when differences in intervention intensity between treatment groups are considered. Rather, evidence from long-term (>=1 year) randomized trials indicates low-carbohydrate or other healthful dietary pattern interventions without a low-fat focus may be more effective for weight loss than low-fat dietary interventions. Further evidence is needed to establish the role of these interventions in longer-term weight loss and weight maintenance.

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Low-Carbohydrate vs. Low-Fat Diets for Weight Loss and Health

Clinical Nutrition INSIGHT ◽

10.1097/01.nmd.0000352302.75455.3b ◽

2009 ◽

Vol 35 (6) ◽

pp. 1-3

Author(s):

Ellen Coleman

Keyword(s):

Weight Loss ◽

Low Fat ◽

Low Carbohydrate ◽

Fat Diets

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Examining differences between overweight women and men in 12-month weight loss study comparing healthy low-carbohydrate vs. low-fat diets

International Journal of Obesity ◽

10.1038/s41366-020-00708-y ◽

2020 ◽

Vol 45 (1) ◽

pp. 225-234

Author(s):

Lucia Aronica ◽

Joseph Rigdon ◽

Lisa C. Offringa ◽

Marcia L. Stefanick ◽

Christopher D. Gardner

Keyword(s):

Weight Loss ◽

Fat Mass ◽

Lean Mass ◽

Secondary Analysis ◽

Low Fat ◽

Primary Analysis ◽

Biological Sex ◽

Low Carbohydrate ◽

Fat Diets ◽

And Behavior

Abstract Background/objectives Biological sex factors and sociocultural gender norms affect the physiology and behavior of weight loss. However, most diet intervention studies do not report outcomes by sex, thereby impeding reproducibility. The objectives of this study were to compare 12-month changes in body weight and composition in groups defined by diet and sex, and adherence to a healthy low carbohydrate (HLC) vs. healthy low fat (HLF) diet. Participants/methods This was a secondary analysis of the DIETFITS trial, in which 609 overweight/obese nondiabetic participants (age, 18–50 years) were randomized to a 12-month HLC (n = 304) or HLF (n = 305) diet. Our first aim concerned comparisons in 12-month changes in weight, fat mass, and lean mass by group with appropriate adjustment for potential confounders. The second aim was to assess whether or not adherence differed by diet-sex group (HLC women n = 179, HLC men n = 125, HLF women n = 167, HLF men n = 138). Results 12-month changes in weight (p < 0.001) were different by group. HLC produced significantly greater weight loss, as well as greater loss of both fat mass and lean mass, than HLF among men [−2.98 kg (−4.47, −1.50); P < 0.001], but not among women. Men were more adherent to HLC than women (p = 0.02). Weight loss estimates within group remained similar after adjusting for adherence, suggesting adherence was not a mediator. Conclusions By reporting outcomes by sex significant weight loss differences were identified between HLC and HLF, which were not recognized in the original primary analysis. These findings highlight the need to consider sex in the design, analysis, and reporting of diet trials.

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