Abstract
The Zone diet is the latest eating regimen marketed to improve athletic performance by opposing traditional high carbohydrate sports diets. The 40/30/30 diet is centred primarily on protein intake (1.8 to 2.2 g/kg fat free mass; i.e. total bodyweight — fat weight) and promises a change in the body’s insulin to glucagon ratio through its macronutrient alterations. Changes in the existing hormonal milieu are said to result in the production of more vasoactive eicosanoids, thus allowing greater oxygen delivery to exercising muscle. This favourable condition, known as the Zone, is anecdotally reported to benefit even the most elite endurance athletes.
Applying the Zone’s suggested protein needs and macronutrient distributions in practice, it is clear that it is a low carbohydrate diet by both relative and absolute standards, as well as calorie deficient by any standard. Reliable and abundant peer reviewed literature is in opposition to the suggestion that such a diet can support competitive athletic endeavours, much less improve them.
The notion that a 40/30/30 diet can alter the pancreatic hormone response in favour of glucagon is also unfounded. The Zone is a mixed diet and not likely to affect pancreatic hormone release in the same way individual nutrients can. Although the postprandial insulin response is reduced when comparing a 40% with a 60% carbohydrate diet, it is still a sufficient stimulus to offset the lipolytic effects of glucagon.
Many of the promised benefits of the Zone are based on selective information regarding hormonal influences on eicosanoid biology. Contradictory information is conveniently left out. The principle of vasodilating muscle arterioles by altering eicosanoid production is notably correct in theory. However, what little human evidence is available does not support any significant contribution of eicosanoids to active muscle vasodilation. In fact, the key eicosanoid reportedly produced in the Zone and responsible for improved muscle oxygenation is not found in skeletal muscle. Based on the best available scientific evidence, the Zone diet should be considered more ergolytic than ergogenic to performance.
This is a preview of subscription content, access via your institution.
References
Simopoulos AP. Opening address. Nutrition and fitness from the first Olympiad in 776 B.C. to 393 A.D. and the concept of positive health. Am J Clin Nutr 1989; 49 Suppl. 5: 921–926
Sears, B. The zone: a dietary road map. New York: Harper Collins, 1995
Costill DL, Bowers R, Kammer WF. Skinfold estimates of body fat among marathon runners. Med Sci Sports Exerc 1970; 2 (2): 93–5
Coleman EJ. Debunking the ‘Eicotec’ myth. Sports Med 1993; 15: 6–7
Coleman EJ. The biozone nutrition system: a dietary panacea? Int J Sport Nutr 1996; 6: 69–71
Bergstrom J, Hultman E. The effect of exercise on muscle glycogen and electrolytes in normals. Scand J Clin Lab Invest 1966; 18: 16–20
Bergstrom J, Hultman E. A study of the glycogen metabolism during exercise in man. Scand J Clin Lab Invest. 1967; 19: 218–28
Lewis SF, Haller RG. The pathophysiology of McArdle’s Disease: clues to regulation in exercise and fatigue. J Appl Physiol 1986; 61: 391–401
Pernow B, Saltin B. Availability of substrates and compacity for prolonged heavy exercise in man. J Appl Physiol 1971; 31 (3): 416–22
Costill D, Coyle E. Energetics of marathon running. Med Sci Sports Exerc 1969; 1: 81–6
O’Brien M, Viguie CA, Mazzeo RS, et al. Carbohydrate dependents during marathon running. Med Sci Sports Exerc 1993; 25 (9): 1009–17
Williams C, Brewer J, Patton A. The metabolic challenge of the marathon. Br J Sports Med 1984; 18: 245–52
Bergstrom J, Hermansen L, Hultman E, et al. Diet, muscle glycogen, and physical performance. Acta Physiol Scand 1967; 71: 140–50
Akermark C, Jacobs R, Rasmusson M, et al. Diet and muscle glycogen concentration in relation to physical performance in Swedish elite hockey players. Int J Sports Nutr 1996; 6: 272–84
Karlsson J, Saltin B. Diet muscle glycogen and endurance performance. J Appl Physiol 1971; 31: 203–6
Sherman W, Costill DL, Fink WJ, et al. Effective exercise-diet manipulation on muscle glycogen and its subsequent utilization during performance. Int J Sports Med 1981; 2: 114–18
Coyle EF, Coggan AR, Hemmert MK, et al. Muscle glycogen utilization during prolonged strenuous exercise when fed carbohydrate. J Appl Physiol 1986; 61: 165–72
Coyle EF, Hagberg JM, Hurley BF, et al. Carbohydrate feeding during prolonged strenuous exercise can delay fatigue. J Appl Physiol 1983; 55: 230–5
Foster C, Costill DL, Fink WJ. Effects of preexercise feeding on endurance performance. Med Sci Sports Exerc 1979; 11: 1–5
Devlin JT, Calles-Escandon J, Horton ES. Effects of preexercise snack feeding on endurance cycle exercise. J Appl Physiol 1986; 60 (3): 980–5
Costill DL, Bowers R, Branam G, et al. Muscle glycogen utilization during prolonged exercise on successive days. J Appl Physiol 1971; 31 (6): 834–8
Costill DL, Sherman WH, Fink DJ, et al. The role of dietary carbohydrates in muscle glycogen resynthesis after strenuous running. Am J Clin Nutr 1981; 34: 1831–6
Simonsen JC, Sherman WM, Lamb DR, et al. Dietary carbohydrate, muscle glycogen, and power output during rowing training. J Appl Physiol 1991; 70 (4): 1500–5
Costill DL, Hinrichs D, Fink WJ, et al. Muscle glycogen depletion during swimming interval training. J Swimming Res 1988; 4: 15–8
Lamb DR, Rinehardt KF, Bartels RL, et al. Dietary carbohydrate and intensity of interval swim training. Am J Clin Nutr 1990; 52: 1058–63
Tarnopolsky MA, Atkinson SA, Phillips SM, et al. Carbohydrate loading and metabolism during exercise in men and women. J Appl Physiol 1995; 78 (4): 1360–8
Muoio DM, Leddy JJ, Horvath PJ, et al. Effect of dietary fat on metabolic adjustments to maximal V. O2max and endurance in runners. Med Sci Sports Exerc 1994; 26: 81–8
Lambert EV, Speechly DP, Dennis SC, et al. Enhanced endurance in trained cyclists during moderate intensity exercise following two weeks adaptation to a high fat diet. Eur J Appl Physiol 1994; 69: 287–93
Sherman WM, Leenders N. Fat loading: the next magic bullet? Int J Sport Nutr 1995; 5 Suppl.: S1–12
Davies CTM, Thompson MW. Aerobic performance of female marathon and male ultramarathon athletes. Eur J Appl Physiol 1979; 41: 233–45
National Research Council. Recommended dietary allowances, 10th ed. Washington DC: National Academy Press, 1989: 29
van Erp-Baart AM, Saris WHM, Binkhorst RA, et al. Nationwide survey on nutritional habits in elite athletes: Part I. Energy, carbohydrates, protein, and fat intake. Int J Sports Med 1989; 10 Suppl. 1: S3–10
Muller WA, Faloona GR, Agullar-Parada E. Abnormal alphacell function in diabetes: response to carbohydrate and protein ingestion. N Engl J Med 1970; 283: 19–115
Coulston AM, Liu GC, Reaven GM. Plasma glucose, insulin and lipid responses to high-carbohydrate low-fat diets in normal humans. Metabolism 1983; 32 (1): 52–6
Lefebvre P, Luyckx A. Effect of insulin on glucagon enhanced lipolysis in vitro. Diabetologia 1969; 5: 195–7
Jensen MD, Caruso M, Heiling V, et al. Insulin regulation of lipolysis in nondiabetic and IDDM subjects. Diabetes 1989; 38: 1595–601
Boyd III AE, Glamber SR, Mager M, et al. Lactate inhibition of lipolysis in exercising man. Metabolism 1974; 23 (6): 531–42
Astrand PO, Ryhming I. A nomagram for calculation of aerobic capacity (physical fitness) from pulse rate during submaximal work. J Appl Physiol 1954; 7: 218–22
Swain DP, Abernathy KS, Smith CS, et al. Target heart rates for the development of cardiorespiratory fitness. Med Sci Sports Exerc 1994; 26 (1): 112–6
Davis JA, Frank MH, Whipp BJ, et al. Anaerobic threshold alterations caused by endurance training in middle-aged men. J Appl Physiol 1979; 46 (6): 1039–46
Roberts KM, Nobel EG, Hayden DB, et al. Simple and complex carbohydrate-rich diets and muscle glycogen content of marathon runners. Eur J Appl Physiol 1988; 57: 70–4
Kiens B, Raben AB, Valeur AK, et al. Benefit of dietary simple carbohydrates on the early postexercise muscle glycogen repletion in male athletes. Med Sci Sports Exerc 1990; 22 (2 Suppl.): S88
Zawadzki KM, Yaspelkis III BB, Ivy JL. Carbohydrate-protein complex increases the rate of muscle glycogen storage after exercise. J Appl Physiol 1992; 72 (5): 1854–9
Spiller GA, Jensen CD, Pattison TS, et al. Effect of protein dose on serum glucose and insulin response to sugars. Am J Clin Nutr 1987; 46: 474–80
Perseghin G, Price TB, Petersen KF, et al. Increased glucose transport-phosphorylation and muscle glycogen synthesis after exercise training in insulin-resistant subjects. N Engl J Med 1996; 335: 1357–62
de Fronzo RA, Ferrannini E, Sato Y, et al. Synergistic interaction between exercise and insulin on peripheral glucose uptake. J Clin Invest 1981; 68: 1468–74
Douen AG, Ramlal T, Rastogi S, et al. Exercise induces recruitment of the ‘insulin-responsive glucose transporter.’ J Biol Chem 1990; 265: 13427–30
Vane JR. Prostaglandins and the cardiovascular system. Br Heart J 1983; 49: 405–9
Messina EJ, Weiner R, Kaley G. Microcirculatory effects of prostaglandin E1, E2, and A1 in the rat mesentary and cremaster muscle. Microvasc Res 1974; 8: 77–89
Bild GS, Bhat SG, Axelrod B, et al. Inhibition of aggregation of human platelets by 8,15-dihydroperoxides or 5,9,11,13- eicosatetraenoic and 9,11,13-eicosatrienoic acids. Prostaglandins 1978; 16: 795–801
Moncada S, Higgs EA, Vane JR. Human arterial and venous tissues generate prostacyclin (prostaglandin X), a potent inhibitor of platelet aggregation. Lancet 1977; I: 18–20
Stone KJ, Willis AL, Hart M, et al. The metabolism of dihomogamma- linolenic acid in man. Lipids 1978; 14 (2): 174–80
Brenner R. The desaturation step in the animal biosynthesis of polyunsaturated fatty acids. Lipids 1971; 6 (8): 567–75
Sprecher H. Biochemistry of essential fatty acids. Prog Lipid Res 1981; 20: 13–22
Bergstrom S, Duner H, von Euler US, et al. Observations on the effects of infusion of prostaglandin E in man. Acta Physiol Scand 1959; 45: 145–50
Ryan MJ, Zimmerman BG. Effect of prostaglandin precursors, dihomo-gamma-linolenic acid and arachadonic acid on the vasoconstriction response to norepinephrine in the dog paw. Prostaglandins 1974; 6 (3): 179–92
Kadowitz PJ. Effect of prostaglandin E1, E2, A2 on vascular resistance and responses to noradrenaline, nerve stimulations, and angiotensin in the dog hindlimb. Br J Pharmacol 1972; 46: 395–400
Kather H, Simon B. Adenylate cyclase of human fat cell ghosts: stimulation of enzyme activity by prostaglandins. J Cyclic Nucleotide Res 1977; 3: 199–206
Herold PM, Kinsella JE. Fish oil consumption and decreased risk of cardiovascular disease: a comparison of findings from animal and human feeding trials. Am J Clin Nutr 1986; 43: 566–98
Simopoulos AP. Omega-3 fatty acids in health and disease and in growth and development. Am J Clin Nutr 1991; 54: 438–63
Thomas LM, Holub BJ. Modification of human platelet phospholipids and agonist-stimulated phosoinositide phosphorylation by omega-3 fatty acids. In: Essential fatty acids and eicosanoids. Champaign: American Oil Chemists Society, 1992: 356–60
Lagarde M, Guichardant M, Dechavanne M. Human platelet PGE1 and diohomogamma linolenic acid. Comparison to PGE2 and arachidonic acid. Prog Lipid Res 1981; 20: 439–43
Willis AL. Unanswered questions in essential fatty acids and prostaglandin research. Prog Lipid Res 1981; 20: 839–50
Willis AL, Comai K, Kuhn DC, et al. Dihomo-gamma-linolenate suppresses platelet aggregration when administered in vitro or in vivo. Prostaglandins 1974; 25: 509–19
Kernoff PBA, Willis AL, Stone KJ, et al. Antithrombotic potential of dihomo-gamma-linolenic acid in man. BMJ 1977; 2 (6100): 1441–4
Fisher JM, Donegan DR, Leon H, et al. Effects of prostaglandins and their precursors in some tests of hemostatic function. Prog Lipid Res 1981; 20: 799–810
Tate G, Mandell BF, Laposata M, et al. Suppression of acute and chronic inflamation by dietary gamma linolenic acid. J Rheumatol 1989; 16 (6): 729–34
Needleman SW, Spector AA, Hoak JC. Enrichment of human phospholipids with linoleic acid diminishes thromboxane release. Prostaglandins 1982; 24: 607–22
Sato T, Nakao K, Hashizume T, et al. Inhibition of platelet aggregation by unsaturated fatty acids through interference with a thomboxane-mediated process. Biochim Biophys Acta 1987; 931: 157–64
Dupont J, Dowe MK. Eicosanoid synthesis as a functional measurement of essential fatty acid requirement. J Am Coll Nutr 1990; 9: 272–6
Shimizu S, Akimoto K, Shinmen Y, et al. Sesamin is a potent and specific inhibitor of delta-5 desaturase in polyunsaturated fatty acid biosynthesis. Lipids 1991; 26: 512–6
de Gomez Dumm INT, de Alaniz MJT, Brenner RR. Effect of diet on linoleic acid desaturation and on some enzymes of carbohydrate metabolism. J Lipid Res 1970; 11: 96–101
Peluffo RO, de Gomez Dumm INT, Brenner RR. The activating of dietary protein on linoleic acid desaturation. Lipids 1972; 7: 363–7
Mimouni V, Poisson JP. Spontaneous diabetes in BB rats: evidence for insulin dependent liver microsomal delta- 6 and delta- 5 desaturase activities. Horm Metab Res 1990; 22: 405–7
Boustani S, Causse J, Descomps B, et al. Direct in vivo characterization of delta-5 desaturase activity in humans by deuterium labeling: effect of insulin. Metabolism 1989; 38 (4): 315–21
Peluffo RO, de Gomez Dumm INT. Effect of protein and insulin on linoleic acid desaturation of normal and diabetic rats. J Nutr 1971; 101: 1075–84
Brenner R. Nutritional and hormonal factors influencing desaturation of essential fatty acids. Prog Lipid Res 1981; 20: 41–7
de Gomez Dumm INT, de Alaniz MJT, Brenner RR. Comparative effects of glucagon, dibutyryl cyclic AMP and epinephrine on the desaturation and elongation of linoleic acid by rat liver microsomes. Lipids 1976; 11 (12): 833–6
de Gomez Dumm INT, de Alaniz MJT, Brenner RR. Effects of glucagon and dibutyryl adenosine 3,5 – cyclic monophosphate on oxidative desaturation of fatty acids in the rat. J Lipid Res 1975; 16: 264–8
Peluffo RO, Brenner RR. Influence of dietary protein on 6 and 9 desaturation of fatty acids in rats of different ages and in different seasons. J Nutr 1974; 104: 894–900
Brenner RR, Peluffo RO, Mercuri O, et al. Effect of arachidonic acid in the alloxan-diabetic rat. Am J Physiol 1968; 215 (1): 63–70
Horton EW, Main IHM. A comparison of the biological activities of four prostaglandins. Br J Pharmacol 1963; 21: 182–9
Beaty III O, Donald DE. Contribution of prostaglandin to muscle blood flow in anesthetized dogs at rest, during exercise, and following inflow occlusion. Circ Res 1979; 44: 67–75
Bergstrom S, Carlson LA, Oro L. Cardiovascular and metabolic response to infusions of prostaglandin E1 and to simultaneous infusions of noradrenaline and prostaglandin E1 in man. Acta Physiol Scand 1965; 64: 332–9
Hedwall PR, Abdel-Sayed WA, Schmid PG, et al. Vascular responses to prostaglandin E1 in gracilis muscle and hindpaw of the dog. Am J Physiol 1971; 221: 42–7
Rotto DM, Kaufman MP. Effect of metabolic products of muscular contraction on discharge group III and IV afferents. J Appl Physiol 1988; 64: 2306–13
Rowell LB, O’Leary DS. Reflex control of the circulation during exercise: chemoreflexes and mechanoreflexes. J Appl Physiol 1990; 69 (2): 407–18
Stebbins CL, Longhurst JC. Potentiation of the exercise pressor reflex by muscle ischemia. J Appl Physiol 1989; 66 (3): 1046–53
Bevegard BS, Shepherd JT. Regulation of the circulation during exercise in man. Physiol Rev 1967; 47: 178–213
Strange S, Secher NH, Pawelczyk JA, et al. Neural control of cardiovascular responses and of ventilation during dynamic exercise in man. J Physiol 1993; 470: 693–704
Rotto DM, Massey KD, Burton KP, et al. Static contraction increases arachidonic acid levels in gastrocnemius muscles of cats. J Appl Physiol 1989; 66: 2721–4
Viinikkia L, Vuori J, Ylikorkala O. Lipid peroxides, prostacyclin, and thromboxane A2 in runners during acute exercise. Med Sci Sports Exerc 1984; 16: 275–7
Stebbins CL, Maruoka Y, Longhurst JC. Prostaglandins contribute to cardiovascular reflexes evoked by static muscular contraction. Circ Res 1986; 59: 645–54
Rotto DM, Schultz HD, Longhurst JC, et al. Sensitization of group III muscle afferents to static contraction by arachadonic acid. J Appl Physiol 1990; 68 (3): 861–7
Wennmalm A, Fitzgerald GA. Excretion of prostacyclin and thromboxane A2 metabolites during leg exercise in humans. Am J Physiol 1988; 255: H15-H8
Ronni-Sivula H, Malm H, Ylikorkala O, et al. Marathon run stimulates more prostacyclin than thromboxane synthesis and differently in men and women. Prostaglandins 1993; 46: 75–9
Koller A, Kaley G. Prostaglandins mediate arteriolar dilation to increase blood flow velocity in skeletal muscle microcirculation. Circ Res 1990; 67: 529–34
Riutta A, Kerttula T, Sievi E, et al. Adrenaline infusion increases systemic prostacyclin production in man. Prostaglandins 1994; 48: 43–51
Jeremy JY, Mikhailidis DP, Dandona P. Adrenergic modulation of vascular prostacyclin (PGI2) secretion. Eur J Pharmacol 1985; 114: 33–40
Wilson JR, Kapoor SC. Contribution of prostaglandins to exerciseinduced vasodilation in humans. Am J Physiol 1993; 265: H171–5
Staessen J, Cattaert A, Fagard R, et al. Hemodynamic and humoral effects of prostaglandin inhibition in exercising humans. J Appl Physiol 1984; 56 (1): 39–45
Carney JA, Slinger SJ, Walker BL. The phospholipid composition of pig lung surfactant. Lipids 1971; 6: 624–9
Karim SMM, Rao B. General introduction and comments. In: Karim SMM, editor. Prostaglandins and reproduction. Baltimore (MD): University Park Press, 1975: 8–9
Ferreira SH, Vane JR. Prostaglandins: their disappearance from and release into the circulation. Nature (Lond) 1967; 216: 868–73
Horton EW. Biological significance of the prostaglandins. In: Gross F, Labhart A, Mann T, et al., editors. Prostaglandins. Heidelberg: Springer-Verlag, 1972: 179–90
Lemon P. Do athletes need more dietary protein and amino acids? Int J Sport Nutr 1995; 5 Suppl.: S39–61
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Cheuvront, S.N. The Zone Diet and Athletic Performance. Sports Med 27, 213–228 (1999). https://doi.org/10.2165/00007256-199927040-00002
Published:
Issue Date:
DOI: https://doi.org/10.2165/00007256-199927040-00002
Keywords
- Adis International Limited
- Glucagon
- Eicosanoid
- Muscle Glycogen
- Athletic Performance