Do We Need More Carbs Before A Sporting Event? Or Will Fat Give Us Enough Energy? A Research Review

Hi everyone, I’m Ashleigh D’Arcy, one of the Dieticians here at Destiny Health! The relationship between fats, carbohydrates and energy in sports has always been a fascinating topic for me.

Every client of mine has unique needs and can therefore benefit from a personalised program. However, below is a summary of what I have found in the scientific literature (references below). I use this knowledge in my everyday work, guiding people to optimal results.   

It’s important to acknowledge that both fat and carbohydrate have been found to be the main fuels for aerobic metabolism (which means using oxygen for energy) during exercise in well-fed people.

We must also remember that the body can turn fat into carbohydrate in a process known as gluconeogenesis (“creating new glucose” in the bloodstream).  

Interestingly, fat has been found to be the dominant energy source at low aerobic power outputs (< 40% VO2max) and provides approximately 50% of the required energy during moderate intensity exercise (~40-65% VO2max).

The contribution from fat decreases at higher power outputs, as carbohydrate is seen to be the main fuel in these instances.

Fat oxidation (breakdown with oxygen) has been found to contribute energy during recovery from a single bout of exercise, and in recovery periods between intense exercise bouts (common in stop-and-go sports). This means that fat is burned after exercise to help us recover. 

Activation of fat oxidation at the onset of exercise is slower than carbohydrates. So, fat appears to be designed for long-term, low to moderate intensity exercise.

Carbohydrate needs seem to vary, depending on the length and intensity of the sporting event. This may be as high as 10-13 grams of carbohydrate per kilogram of body weight per day for endurance sport athletes.

A 60 kilogram athlete participating in a 1-1.5 hour gym session may safely consume 60-90g of carbohydrates before their training session, whilst a 60kg athlete performing a 2-3 hour cycling session would benefit more from 180-240g of carbohydrates prior to the session, to ensure adequate energy levels throughout the race.

A few examples of 50g carbohydrate food/ drinks include:

500ml of fruit juice

50g of jellybeans

1 cup of cooked rice

3 pieces of medium fruit

If your goal is increased performance in a 90 minute gym session, the research suggests that 500ml of fruit juice before hand will aid your performance.

What are your specific goals? And does this information help you in your sport?

At Destiny Health, our team of Dieticians take a deep dive into your lifestyle, history and goals, to customise the ideal program for you.

If you’re busy juggling training and career goals, if you want to gain THE EDGE in your performance, and if you’re SERIOUS about results, then why not register your interest in a FREE ASSESSMENT today?

Simply call 1300 GYM DOC (1300 496 362).   

Ashliegh : )

B.Nut.Diet (Hons), APD

References:

Achten, J., M. Gleeson, and A.E. Jeukendrup (2002). Determination of the exercise intensity that elicits maximal fat oxidation. Med. Sci. Sports Exerc. 34: 92-97.

Alsted, T.J., L. Nybo, M. Schweiger, C. Fledelius, P. Jacobsen, R. Zimmermann, R. Zechner, and B. Kiens (2009). Adipose triglyceride lipase in human skeletal muscle is upregulated by exercise training. Am. J. Physiol. 296:E445-453.

Bonen, A., J.J. Luiken, Y. Arumugam, J.F. Glatz, and N.N. Tandon (2000). Acute regulation of fatty acid uptake involves the cellular redistribution of fatty acid translocase. J. Biol. Chem. 275:14501-14508.

Bradley, N.S., L.A. Snook, S.S. Jain, G.J.F. Heigenhauser, A. Bonen, and L. . Spriet (2012). Acute endurance exercise increases plasma membrane fatty acid transport proteins in rat and human skeletal muscle. Am. J. Physiol. 302:E183-189.

Burke, L.M, & Deakin, V 2015, Clinical Sports Nutrition, McGraw-Hill Education (Australia) Pty Limited, North Ryde. Available from: ProQuest Ebook Central. [4 April 2023].

Burke, L.M., Cox, G.R., Cummings, N.K. et al. Guidelines for Daily Carbohydrate Intake. Sports Med 31, 267–299 (2001). https://doi.org/10.2165/00007256-200131040-00003.

Coggan, A.R., C.A. Raguso, B.D. Williams, L.S. Sidossis, and A. Gastaldelli (1995a). Glucose kinetics during high-intensity exercise in endurance-trained and untrained humans. J. Appl. Physiol. 78:1203-1207.

Coggan, A.R., S.C. Swanson, L.A. Mendenhall, D.L. Habash, and C.L. Kien (1995b). Effect of endurance training on hepatic glycogenolysis and gluconeogenesis during prolonged exercise in men. Am. J. Physiol. 268:375-383.

Decombaz, J., B. Schmitt, M. Ith, B. Decarli, P. Diem, R. Kreis, H. Hoppeler, and C. Boesch (2001). Postexercise fat intake repletes intramyocellular lipids but no faster in trained than in sedentary subjects. Am. J. Physiol. 281:R760-R769.

Fentz. J., R. Kjobsted, J.B. Birk, J. Jeppesen, K. Thorsen, P. Schjerling, B. Kiens, N. Jessen, B. Viollet, and J.F. Wojtaszewski (2015). AMPKα is critical for enhancing skeletal muscle fatty acid utilization during in vivo exercise in mice. FASEB J. 29:1725-1738.

Goodpaster, B.H., J. He, S. Watkins, and D.E. Kelley (2001). Skeletal muscle lipid content and insulin resistance: evidence for a paradox in endurance-trained athletes. J. Clin. Endocrinol. Metab. 86:755–5761.

Glatz, J.F., J.J. Luiken, and A. Bonen (2010). membrane fatty acid transporters as regulators of lipid metabolism; Implications for metabolic disease. Physiol. Rev. 90:367-417.

Hargreaves, M., and L.L. Spriet (2017). Exercise metabolism: Fuels for the fire. In: The Biology of Exercise. Zierath, J.R., M.J. Joyner, and J.A. Hawley (eds). Cold Spring Harbor Laboratory Press. Cold Spring Harbor, USA. pp. 57-72.

Henderson, G.C., J.A. Fattor, M.A. Horning, N. Faghihnia, M.L. Johnson, T.L. Mau, M. Luke-Zeitoun, and G.A. Brooks (2007). Lipolysis and fatty acid metabolism in men and women during the postexercise recovery period. J. Physiol. 584:963-981.

Holloway, G.P., and L.L. Spriet (2009). Skeletal muscle metabolic adaptations to training. In: The IOC Textbook of Science in Sport. R.J. Maughan (Ed): O. Wiley-Blackwell, UK.pp. 70-83.

Holloway, G.P., V. Bezaire, G.J.F. Heigenhauser, N.N. Tandon, J.F. Glatz, J.J. Luiken, A. Bonen, and L. L. Spriet (2006). Mitochondrial long chain fatty acid oxidation, fatty acid translocase/CD36 content and carnitine palmitoyltransferase I activity in human skeletal muscle during aerobic exercise. J Physiol 571: 201-210.

Holloszy, J.O. (1967). Biochemical adaptations in muscle. Effects of exercise on mitochondrial oxygen uptake and respiratory enzyme activity in skeletal muscle. J. Biol. Chem. 242:2278–2282.

Holloszy, J.O., and E.F. Coyle (1984). Adaptations of skeletal muscle to endurance exercise and their metabolic consequences. J. Appl. Physiol. 56:831–838.

Holloszy, J.O., L.B. Oscai, I.J. Don, and P.A. Mole (1970) Mitochondrial citric acid cycle and related enzymes: adaptive response to exercise. Biochem. Biophys. Res. Commun. 40:1368–1373.

Howlett, R.A., M.L. Parolin, D.J. Dyck, E. Hultman, N.L. Jones, G.J.F. Heigenhauser, and L.L. Spriet (1998). Regulation of skeletal muscle glycogen phosphorylase and pyruvate dehydrogenase at varying power outputs. Am. J. Physiol. 275:R418-R425.

Jain, S.S., A. Chabowski, L.A. Snook, R.W. Schwenk, J.F. Glatz, J.J. Luiken, and A. Bonen (2009). Additive effects of insulin and muscle contraction on fatty acid transport and fatty acid transporters, FAT/CD36, FABPpm, FATP1, 4 and 6. FEBS Lett. 583:2294-2300.

Jain, S.S., J.J. Luiken, L.A. Snook, X.X. Han, G.P. Holloway, J.F. Glatz, and A. Bonen (2015). Fatty acid transport and transporters in muscle are critically regulated by Akt2.589:2769-2775.

Jevons, E.F.P., K.D. Gejl, J.A. Strauss, N. Ortenblad, and S.O. Shepherd (2020). Skeletal muscle lipid droplets are resynthesized before being coated with perilipin proteins following prolonged exercise in elite male triathletes. Am. J. Physiol. 318:E357-E370.

Kiens, B. (2006). Skeletal muscle lipid metabolism in exercise and insulin resistance. Physiol Rev 86:205-243.

Kiens, B., and E.A. Richter (1998). Utilization of skeletal muscle triacylglcerol during postexercise recovery in humans. Am. J. Physiol. 275:E332-E337.

Kimber, N.E., G.J.F. Heigenhauser, L.L. Spriet, and D.J. Dyck (2003). Skeletal muscle fat and carbohydrate metabolism during recovery from glycogen-depleting exercise in humans. J. Physiol. 548:919-927.

Larson-Meyer, D.E., B.R. Newcomer, and G.R. Hunter (2002). Influence of endurance running and revovery diet on intramyocellular lipid content in women: a 1H NMR study. Am. J. Physiol. 282:E95-E106.

MacPherson, R.E., and S.J. Peters (2015). Piecing together the puzzle of perilipin proteins and skeletal muscle lipolysis. Appl. Physiol. Nutr. Metab. 40:641-651.

Malatesta, D., C. Werlen, S. Bulfaro, X. Cheneviere, and F. Borrani (2009). Effect of high-intensity interval exercise on lipid oxidation during postexercise recovery. Med. Sci. Sports Exerc. 41:364-374.

Mole, P.A., L.B. Oscai, and J.O. Holloszy (1971). Adaptation of muscle to exercise. Increase in levels of palmityl CoA synthetase, carnitine palmityltransferase, and palmityl CoA

dehydrogenase, and in the capacity to oxidize fatty acids. J. Clin. Invest. 50:2323–2330.

Perry, C.G., G.J.F. Heigenhauser, A. Bonen, and L.L. Spriet (2008). High-intensity aerobic interval training increases fat and carbohydrate metabolic capacities in human skeletal muscle. Appl. Physiol. Nutr. Metab. 33:1112-1123.

Petrick, H.L., and G.P. Holloway (2019). High intensity exercise inhibits carnitine palmitoyltransferase-I sensitivity to l-carnitine. Biochem. J. 476:547-558.

Prats, C., M. Donsmark, K. Qvortrup, C. Londos, C. Sztalryd, C. Holm, H. Galbo, and T. Ploug (2006). Decrease in intramuscular lipid droplets and translocation of HSL in response to muscle contraction and epinephrine. J. Lipid Res. 47:2392-2399.

Randell, R.K., and L.L. Spriet (2020). Factors affecting fat oxidation rates in athletes. Sports Science Exchange #206 .

Randell, R.K., I. Rollo, T.J. Roberts, K J. Dalrymple, A.E. Jeukendrup, and J.M. Carter (2017). Maximal fat oxidation rates in an athletic population. Med. Sci. Sports Exerc. 49:133-140.

Romijn, J.A., E.F. Coyle, L.S. Sidossis, A. Gastaldelli, J.F. Horowitz, E. Endert, and R.R. Wolfe (1993). Regulation of endogenous fat and carbohydrate metabolism in relation to exercise intensity and duration. Am. J. Physiol. 265:E380-391.

Romijn, J.A., E.F. Coyle, L.S. Sidossis, J. Rosenblatt, and R.R. Wolfe (2000). Substrate metabolism during different exercise intensities in endurance-trained women. J. Appl. Physiol. 88:1707-1714.

Sahlin, K. (2009). Control of lipid oxidation at the mitochondrial level. Appl. Physiol. Nutr. Metab. 34:382-388.

Shepherd, S.O., M. Cocks, K.D. Tipton, A.M. Ranasinghe, T.A. Barker, J.G. Burniston, A.J.M. Wagenmakers, and C.S. Shaw (2013). Sprint interval and traditional endurance training increase net intramuscular triglyceride breakdown and expression of perilipin 2 and 5. J. Physiol. 591:657-675.

Shepherd, S.O., M. Cocks, K.D. Tipton, O.C. Witard, A.M. Ranasinghe, T.A. Barker, A.J.M. Wagenmakers, and C.S. Shaw (2014). Resistance training increases skeletal muscle oxidative capacity and net intramuscular triglyceride breakdown in type I and II fibers of sedentary males. Exp. Physiol. 99:894-908.

Smith, B.K., C.G. Perry, T.R. Koves, D.C. Wright, J.C. Smith, P.D. Neufer, D.M. Muoio, and G.P. Holloway (2012a). Identification of a novel malonyl-CoA IC50 for CPT-1: Implications for predicting in vivo fatty acid oxidation rates. Biochem. J. 448:13–20.

Smith, B.K., A. Bonen and G.P. Holloway (2012b). A dual mechanism of action for skeletal muscle FAT/CD36 during exercise. Exerc. Sport Sci. Rev. 40:211-217.

Spriet, L.L. (2012). The metabolic systems: Lipid metabolism. In: Farrell, P.A., M.J. Joyner, and V.J. Caiozzo, (eds). Advanced Exercise Physiology, 2nd Ed. W. Lippincott, Wilkins.Philadelphia, PA, USA. pp. 392-407.

Spriet, L.L. (2014). New insights into the interaction of carbohydrate and fat metabolism during exercise. Sports Med. 44:S87-S96.

Stefanyk, L.E., A. Bonen, and D.J. Dyck (2012). Insulin and contraction-induced movement of fatty acid transport proteins to skeletal muscle transverse tubules is distinctly different

than to the sarcolemma. Metabolism 61:1518–1522.

Stellingwerff, T., H. Boon, R.A. Jonkers, J.M. Senden, L.L. Spriet, R. Koopman, and L.J. van Loon (2007). Significant intramyocellular lipid use during prolonged cycling in endurance-trained males as assessed by three different methodologies. Am. J. Physiol. 292:E1715-1723.

Talanian, J.L., G.P. Holloway, L.A. Snook, G.J.F. Heigenhauser, A. Bonen, and L.L. Spriet (2010). Exercise training increases sarcolemmal and mitochondrial fatty acid transport proteins in human skeletal muscle. Am. J. Physiol. 299:E180-188.

Turcotte, L., B. Kiens, and E.A. Richter (1991). Saturation kinetics of palmitate uptake in perfused skeletal muscle. FEBS Lett.279:327–329.

Turcotte, L.P., E.A. Richter, and B. Kiens (1992). Increased plasma FFA uptake and oxidation during prolonged exercise in trained vs. untrained humans. Am. J. Physiol. 262:E791–E799.

Turcotte, L.P., J.R. Swenberger, M.Z. Tucker, A.J. Yee, G. Trump, J.J. Luiken, and A. Bonen

(2000). Muscle palmitate uptake and binding are saturable and inhibited by antibodies to FABP(PM). Mol. Cell. Biochem. 210:53–63.

van Loon, L.J., P.L. Greenhaff, D. Constantin-Teodosiu, W.H. Saris and A.J. Wagenmakers (2001). The effects of increasing exercise intensity on muscle fuel utilisation in humans. J. Physiol. 536: 295-304.

Watt, M.J., G.J.F. Heigenhauser, D.J. Dyck, and L.L. Spriet (2002). Intramuscular triacylglycerol, glycogen and acetyl group metabolism during 4 h of moderate exercise in man. J. Physiol. 541:969-978.