Can Low-fat Foods Contribute to Obesity?
A Cornell University study showed people ate an average of 28% more total calories when they ate low-fat snacks as compared to regular ones.
Wansink, Brian and Pierre Chandon (2006), Can "Low-Fat" Nutrition Labels Lead to Obesity?, Journal of Marketing Research, 43:4, 605-17.
Moderately High Protein Diet Findings
- > weight loss
- > loss of body fat
- > sparing of muscle protein
- > stability of blood sugar
- < triglycerides
Layman DK et al. (2003). A reduced ratio of dietary carbohydrate to protein improves body composition and blood lipid profiles during weight loss in adult women. J Nutr.;133:411-417.
Very Low Carbohydrate diet have been shown to be more effective for short-term weight loss (less than 6 months to 1 year) than calorie restrictive diet and/or low fat diets. Improvements in blood pressure, lipids, fasting glucose, and insulin were also observed.
Brehm BJ, Seeley RJ, Daniels SR, D'Alessio DA (2003). A randomized trial comparing a very low carbohydrate diet and a calorie-restricted low fat diet on body weight and cardiovascular risk factors in healthy women. J Clin Endocrinol Metab. 88(4):1617-23.
Foster GD, Wyatt HR, Hill JO, McGuckin BG, Brill C, Mohammed BS, Szapary PO, Rader DJ, Edman JS, Klein S (2003). A randomized trial of a low-carbohydrate diet for obesity. N Engl J Med. May 22;348(21):2082-90.
Samaha FF, Iqbal N, Seshadri P, Chicano KL, Daily DA, McGrory J, Williams T, Williams M, Gracely EJ, Stern L (2003). A low-carbohydrate as compared with a low-fat diet in severe obesity. N Engl J Med. 348(21):2074-81.
Low Carb Diet Meta Studies
Meta studies performed in 2003 could not find sufficient evidence to make recommendations for or against the use of low-carbohydrate diets (Bravata 2003). Meta analysis in 2006 found favorable data to support the efficacy of Low Carbohydrate diets (Krieger 2006). Krieger et al. (2006) also noted protein intakes of >1.05 g/kg were associated with 0.6 kg additional fat-free mass retention.
Bravata DM, Sanders L, Huang J, Krumholz HM, Olkin I, Gardner CD, Bravata DM (2003). Efficacy and safety of low-carbohydrate diets: a systematic review. JAMA. 9;289(14):1837-50.
Krieger JW, Sitren HS, Daniels MJ, Langkamp-Henken B (2006). Effects of variation in protein and carbohydrate intake on body mass and composition during energy restriction: a meta-regression 1. Am J Clin Nutr. 83(2):260-74.
Low Carb Combined with High Protein or High Fat
A hypo-caloric (1433 kcal) low carbohydrate (36% carbs) diet with either high protein (34% protein, 29% fat) or high monosaturated fat (18% protein, 45% fat) resulted in similar weight loss, insulin resistance, and cardiovascular disease risk factors. However, the high protein diet had less loss of the thermic effect of feeding. Neither diet had any detrimental effects on bone turnover or renal function.
Luscombe-Marsh ND, Noakes M, Wittert GA, Keogh JB, Foster P, Clifton PM (2005). Carbohydrate-restricted diets high in either monounsaturated fat or protein are equally effective at promoting fat loss and improving blood lipids. Am J Clin Nutr. 81(4):762-72.
Low Carb versus Very Low Carb
Johnston et al 2006 found that a ketogenic low-carbohydrate diet (beginning with ~5% carbohydrate, 60% fat) and nonketogenic low-carbohydrate diet (40% carbohydrate, 30% fat) were equally effective in reducing body weight and insulin resistance. However, ketogenic group experienced several adverse metabolic and emotional effects such as higher inflammatory risk (arachidonic acid:eicosapentaenoic acid ratios in plasma phospholipids) and lower perceptions vigor.
Johnston CS, Tjonn SL, Swan PD, White A, Hutchins H, & Sears B (2006). Ketogenic low-carbohydrate diets have no metabolic advantage over nonketogenic low-carbohydrate diets. American Society for Clinical Nutrition: 83, 5: 1055-1061.
The A TO Z Weight Loss Study
Premenopausal overweight and obese women (mean: age 41, 85 kg) who were randomly assigned to the Atkins diet lost significantly more weight (-4.7 kg) and had more favorable overall metabolic effects at 12 months than any other treatment group including Zone (1.6 kg), LEARN (2.6 kg), and Ornish (2.2 kg).
Gardner CD, Kiazand A, Alhassan S, Kim S, Stafford RS, Balise RR, Kraemer HC, King AC (2007). Comparison of the Atkins, Zone, Ornish, and LEARN diets for change in weight and related risk factors among overweight premenopausal women: the A TO Z Weight Loss Study: a randomized trial. JAMA. 297(9):969-77.
Low Carb, Low Fat, or Mediterranean Diet
Moderately obese subjects (86% male; Mean: age 52, BMI 31) were randomly assigned to one of three groups for 2 years. Adherence to a study diet was 95.4% at 1 year and 84.6% at 2 years
- Low Carb (-5.5 kg)
- 20g Carbs/day for 2 months
- 120 g per day for weight maintenance
- non-calorie restrictive, urged to use vegetarian sources of fat and protein
- Average weight loss was 4.7 kg
- Experienced most favorable effects on lipids
- Mediterranean diet (-4.6 kg)
- <35% Fat with olive oil and nuts
- Men 1800 kcal/day
- Women 1500 kcal/day
- Average weight loss was 4.4 kg
- Experienced most favorable glycemic control
- Low Fat (-3.3 kg)
- 30% Fat, 10% Saturated Fat
- Men 1800 kcal/day
- Women 1500 kcal/day
- Average weight loss was 2.9 kg
Shai I, et al. (2008). Weight loss with a low-carbohydrate, Mediterranean, or low-fat diet. N Engl J Med. 359 (3): 229-41.
- Protein is more satiating than carbohydrate and fat.
- Animal protein induces a higher thermogenesis than vegetable protein.
- High-protein diets affect body weight loss positively only under ad-libitum energy intake conditions, suggesting a resulting decrease energy intake.
- High protein diets improve body composition and metabolic profile.
- After weight loss, additional protein consumption results in a significantly lower body weight regain
- due to body composition, satiety, thermogenesis, and energy inefficiency
- metabolic profile improves further
Westerterp-Plantenga MS (2003). The significance of protein in food intake and body weight regulation. Curr Opin Clin Nutr Metab Care. 6(6):635-8.
"Hence the most reasonable treatment of obesity is to limit the use of non-protein foods and to indulge in hard muscular work."
Hough T & Sedgwick WT (1906). The Human Mechanism, Ginn & Company, pg 236.