Immunological Effects of Low-Fat Diets with and without Weight Loss

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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Low-fat diets and energy balance: how does the evidence stand in 2002?

Proceedings of The Nutrition Society ◽

10.1079/pns2002149 ◽

2002 ◽

Vol 61 (2) ◽

pp. 299-309 ◽

Cited By ~ 68

Author(s):

Arne Astrup ◽

Benjamin Buemann ◽

Anne Flint ◽

Anne Raben

Keyword(s):

Weight Loss ◽

Fatty Acid ◽

Weight Gain ◽

Intervention Study ◽

Glycaemic Index ◽

Low Fat ◽

Low Fat Diet ◽

Acid Diet ◽

Ad Libitum ◽

Fat Diets

The role of high-fat diets in weight gain and obesity is assessed by evidence-based principles. Four meta-analyses of weight change occurring onad libitumlow-fat diets in intervention trials consistently demonstrate a highly significant weight loss of 3–4 kg in normal-weight and overweight subjects (P< 0·001). The analyses also find a dose-response relationship, i.e. the reduction in percentage energy as fat is positively associated with weight loss. Weight loss is also positively related to initial weight; a 10 % reduction in dietary fat is predicted to produce a 4–5 kg weight loss in an individual with a BMI of 30kg/m2. The non-fat macronutrient composition of the diet is also important. Whereas the glycaemic index of the carbohydrate may play a role for cardiovascular risk factors, there is so far no evidence that low-glycaemic index foods facilitate weight control. In contrast, intervention studies show that sugar in drinks is more likely to produce weight gain than solid sugar in foods. Although the evidence is weak, alcoholic beverages promote a positive energy balance, and wine may be more obesity-promoting than beer. Protein is more satiating and fhermogenic than carbohydrates, and one intervention study has shown that anad libitumlow-fat diet where carbohydrate was replaced by protein produced more weight loss after 6 months (8·1v. 5·9 kg). The evidence linking particular fatty acids to body fatness is weak. If anything, monounsaturated fat may be more fattening than polyunsaturated and saturated fats, and noad libitumdietary intervention study has shown that a normal-fat high-monounsaturated fatty acid diet is equivalent or superior to a low-fat diet in the prevention of weight gain and obesity. The evidence strongly supports the low-fat diet as the optimal choice for the prevention of weight gain and obesity, while the use of a normal-fat high-monounsaturated fatty acid diet is unsubstantiated.

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The Effect of High-, Moderate-, and Low-Fat Diets on Weight Loss and Cardiovascular Disease Risk Factors

Preventive Cardiology ◽

10.1111/j.1520-037x.2002.01231.x ◽

2002 ◽

Vol 5 (3) ◽

pp. 110-203 ◽

Cited By ~ 52

Author(s):

Richard M. Fleming

Keyword(s):

Risk Factors ◽

Cardiovascular Disease ◽

Weight Loss ◽

Disease Risk ◽

Cardiovascular Disease Risk ◽

Cardiovascular Disease Risk Factors ◽

Low Fat ◽

Fat Diets

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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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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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