The Role of Dietary Fat in Obesity

ABSTRACT

Current scientific evidence indicates that dietary fat plays a role in weight loss and maintenance. Meta-analyses of intervention trials find that fat-reduced diets cause a 3-4-kg larger weight loss than normal-fat diets. A 10% reduction in dietary fat can cause a 4-5-kg weight loss in individuals with initial body mass index of 30 kg m^-2. Short-term trials show that nonfat dietary components are equally important. Sugar-sweetened beverages promote weight gain, and replacement of energy from fat by sugar-sweetened beverages is counterproductive in diets aimed at weight loss. Protein has been shown to be more satiating than carbohydrate, and fat-reduced diets with a high protein content (20-25% of energy) may increase weight loss significantly. There is little evidence that low-glycemic index foods facilitate weight control. Evidence linking certain fatty acids to body fatness is weak. Monounsaturated fatty acids may even be more fattening than polyunsaturated and saturated fats. No ad libitum dietary intervention study has shown that a normal-fat, high-monounsaturated fatty acid diet is comparable to a low-fat diet in preventing weight gain. Current evidence indicates that the best diet for prevention of weight gain, obesity, type 2 diabetes, and cardiovascular disease is low in fat and sugar-rich beverages and high in carbohydrates, fiber, grains, and protein.

KEYWORDS

Fat-reduced diets - food pyramid - glycemic index - low-fat diets - weight loss

REFERENCES

• 1 National Institutes of Health .The Practical Guide: Identification, Evaluation, and Treatment of Overweight and Obesity in Adults. Publication 00-4084 Bethesda, MD; National Institutes of Health 2000
• 2 Eurodiet core report. Nutrition and diet for healthy lifestyles in Europe: science and policy implications.  Public Health Nutr. 2001;  4 265
• 3 Willett W C. Is dietary fat a major determinant of body fat?.  Am J Clin Nutr. 1998;  67 (3 suppl) 556S-562S
• 4 Willett W C. Eat, Drink and be Healthy. A Harvard Medical School Book New York; Simon and Schuster 2001
• 5 Eccles M, Freemantle N, Mason J. North of England evidence based guidelines development project: methods of developing for efficient drug use in primary care.  BMJ. 1998;  316 1232-1235
• 6 Rolls B J, Hammer V A. Fat, carbohydrate, and the regulation of energy intake.  Am J Clin Nutr. 1995;  62(5 suppl) 1086S-1095S
• 7 Bray G A, Popkin B M. Dietary fat intake does affect obesity.  Am J Clin Nutr. 1998;  68 1157-1173
• 8 Astrup A, Ryan L, Grunwald G K et al.. The role of dietary fat in body fatness: evidence from a preliminary meta-analysis of ad libitum low fat dietary intervention studies.  Br J Nutr. 2000;  83(Suppl 1) S25-S32
• 9 Yu-Poth S, Zhao G, Etherton T et al.. Effects of the National Cholesterol Education Programs step I and step II dietary intervention programs on cardiovascular disease risk factors: a meta-analysis.  Am J Clin Nutr. 1999;  69 632-646
• 10 Astrup A, Grunwald G K, Melanson E L, Saris W H, Hill J O. The role of low-fat diets in body weight control: a meta-analysis of ad libitum intervention studies.  Int J Obes Relat Metab Disord. 2000;  24 1545-1552
• 11 Pirozzo S, Summerbell C, Cameron C, Galsziou P. Should we recommend low-fat diets for obesity?.  Obes Rev. 2003;  4 83-90
• 12 Hill J O, Astrup A. What diets should we be recommending for obesity?.  Obes Rev. 2003;  4 77-78
• 13 Singh R B, Rastogi S S, Verma R et al.. Randomised controlled trial of cardioprotective diet in patients with recent acute myocardial infarction: result of one-year follow up.  BMJ. 1992;  304 1015-1019
• 14 Singh R B, Dubnov G, Niaz M A et al.. Effect of an Indo-Mediterranean diet on progression of coronary artery disease in high risk patients (Indo-Mediterranean Diet Heart Study): a randomised single-blind trial.  Lancet. 2002;  360 1455-1461
• 15 Tuomilehto J, Lindström J, Eriksson J G et al.. Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance.  N Engl J Med. 2001;  344 1343-1350
• 16 Knowler W C, Barrett-Connor E, Fowler S E et al.. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin.  N Engl J Med. 2002;  346 393-403
• 17 Sjöström L, Togerson J S, Hauptman J, Boldrin M. XENDOS-a landmark study: xenical in the prevention of diabetes in obese subjects, in Abstracts from the Satellite Symposium New Frontiers in Weight Management, 9th International Congress on Obesity, São Paulo, Brazil 2002
• 18 Ornish D, Brown S E, Scherwitz L W et al.. Can lifestyle changes reverse coronary heart disease?.  Lancet. 1990;  336 129-133
• 19 Swinburn B A, Metcalf P A, Ley S J. Long-term (5-year) effects of a reduced-fat diet intervention in individuals with glucose intolerance.  Diabetes Care. 2001;  24 619-624
• 20 Pi-Sunyer F X. Glycemic index and disease.  Am J Clin Nutr. 2002;  76 290S-298S
• 21 Raben A, Vasilaras T H, Møller A C, Astrup A. Sucrose compared with artificial sweeteners: different effects on ad libitum food intake and body weight after 10 wk of supplementation in overweight subjects.  Am J Clin Nutr. 2002;  76 721-729
• 22 Pawlak D B, Ebbeling C B, Ludwig D S. Should obese patients be counselled to follow a low-glycaemic index diet? Yes.  Obes Rev. 2002;  3 235-243
• 23 Møller B K, Flint A, Pedersen D et al.. Prediction of glycemic index in mixed meals. Oral presentation. Proceedings of the 12th European Congress on Obesity, Helsinki, 29 May-1 June, 2003.  Int J Obes. 2003;  27(suppl 1) S38
• 24 Saris W H, Astrup A, Prentice A M et al.. Randomized controlled trial of changes in dietary carbohydrate/fat ratio and simple vs. complex carbohydrates on body weight and blood lipids: the CARMEN study.  Int J Obes Relat Metab Disord. 2000;  24 1310-1318
• 25 Miles C. The metabolizable energy of diets differing in dietary fat and fiber measured in humans.  J Nutr. 1992;  122 306-311
• 26 Baer D J, Rumpler W V, Miles C W, Fahey Jr G C. Dietary fiber decreases the metabolizable energy content and nutrient digestibility of mixed diets fed to humans.  J Nutr. 1997;  127 579-586
• 27 Tordoff M G, Alleva M. Effect of drinking soda sweetened with aspartame or high-fructose corn syrup on food intake and body weight.  Am J Clin Nutr. 1990;  51 963-969
• 28 Porikos K P, Hesser M F, van Itallie T B. Caloric regulation in normal-weight men maintained on a palatable diet of conventional foods.  Physiol Behav. 1982;  29 293-300
• 29 Di Meglio D P, Mattes R D. Liquid versus solid carbohydrate: effects on food intake and body weight.  Int J Obes Relat Metab Disord. 2000;  24 794-800
• 30 Ludwig D S, Peterson K E, Gortmaker S L. Relation between consumption of sugar-sweetened drinks and childhood obesity: a prospective, observational analysis.  Lancet. 2001;  357 505-508
• 31 Hoppe C, Mølgaard C, Juul A, Michaelsen K F. Protein intake in infancy is related to body size but not to adiposity in 10-y old children.  Int J Obes Relat Metab Disord. 2001;  25(suppl 2) S64
• 32 Skov A R, Toubro S, Rønn B et al.. Randomized trial on protein versus carbohydrate in ad libitum fat reduced diet for the treatment of obesity.  Int J Obes Relat Metab Disord. 1999;  23 528-536
• 33 Haulrik N, Toubro S, Dyerberg J et al.. Effect of protein and methionine intakes on plasma homocysteine concentrations: a 6-mo randomized controlled trial in overweight subjects.  Am J Clin Nutr. 2002;  76 1202-1206
• 34 Skov A R, Toubro S, Bülow J et al.. Changes in renal function during weight loss induced by high vs. low protein low-fat diets in overweight subjects.  Int J Obes. 1999;  23 1170-1177
• 35 Skov A R, Haulrik N, Toubro S et al.. Effect of protein intake on bone mineralisation during weight loss: a 6-month trial.  Obes Res. 2002;  10 432-438
• 36 Shimomura Y, Tamura T, Suzuki M. Less body fat accumulation in rats fed a safflower oil diet than in rats fed a beef tallow diet.  J Nutr. 1990;  120 1291-1296
• 37 Dulloo A G, Mensi N, Seydoux J, Girardier L. Differential effects of high-fat diets varying in fatty acid composition on the efficiency of lean and fat tissue deposition during weight recovery after low food intake.  Metabolism. 1995;  44 273-279
• 38 Matsuo T, Shimomura Y, Saitoh S et al.. Sympathetic activity is lower in rats fed a beef tallow diet than rats fed a safflower oil diet.  Metabolism. 1995;  44 934-939
• 39 Hill J O, Peters J C, Lin D et al.. Lipid accumulation and body fat distribution is influenced by type of dietary fat fed to rats.  Int J Obes Relat Metab Disord. 1993;  17 223-236
• 40 Doucet N A, White M D, DespreŽs J-P et al.. Dietary fat composition and human adiposity.  Eur J Clin Nutr. 1998;  52 2-6
• 41 Colditz G A, Willett W C, Stampfer M J et al.. Patterns of weight change and their relation to diet in a cohort of healthy women.  Am J Clin Nutr. 1990;  51 100-105
• 42 van Dam R M, Stampfer M, Willett W C et al.. Dietary fat and meat intake in relation to risk of type 2 diabetes in men.  Diabetes Care. 2002;  25 417-424
• 43 Lawton C L, Delargy H J, Brockman J et al.. The degree of saturation of fatty acids influences post-ingestive satiety.  Br J Nutr. 2000;  83 473-482
• 44 Flint A, Jørgensen B H, Raben A et al.. No differences in appetite and energy expenditure after intake of polyunsaturated, monounsaturated or trans-fatty acids.  Obes Res. 2003;  , In press
• 45 Wolever T MS, Jenkins D JA, Vuksan V et al.. Beneficial effect of low-glycemic index diet in overweight NIDDM subjects.  Diabetes Care. 1992;  15 562-564
• 46 Wolever T MS, Mehling C. High-carbohydrate//low glycaemic index dietary advice improves glucose disposition index in subjects with impaired glucose tolerance.  Br J Nutr. 2002;  87 477-487
• 47 Astrup A. Dietary fat and obesity: still an important issue.  Scan J Nutr. 2003;  47 50-57
• 48 Wolever T MS, Mehling C. Long-term effect of varying the source of dietary carbohydrate on postprandial plasma glucose, insulin, triacylglycerol, and free fatty acid concentrations in subjects with impaired glucose tolerance.  Am J Clin Nutr. 2003;  77 612-621