High fat diet improves performance, lipid profilie and immune function in endurance athletes


Matti Narkia

Several studies seem to suggest that relatively high fat
diets improve performance, lipid profile and immune function in endurance
athletes. Below a few news articles about studies conducted at the
University of Buffalo in 1994, 1997 and 1999 (references [31] and [29] in
the reference list at the bottom of this message):

Trained Runners Perform Better On Diet Moderately High In Fat Than On High-Carbohydrate, Low-Fat
Regimen, Study Shows October 25, 1994 <URL:http://www.buffalo.edu/news/fast-execute.cgi/article-


"Highly trained runners hoping to improve their performance by slashing fat from their diets may
be heading down the wrong nutritional path, a small pilot study by University at Buffalo
researchers implies.


Historically, researchers have agreed that a high- carbohydrate, low-fat diet is preferred for
maximum endurance during moderate-to-high-intensity exercise. Many of the studies supporting
this view have used untrained or moderately trained subjects, Leddy said. Those results may not
apply to trained runners because trained athletes metabolize fats more efficiently that
untrained persons, he noted.

Previous studies using a high-fat diet often severely restricted carbohydrates as well, Leddy
said, while carbohydrate levels remained at 50 percent of total calories even on the increased-
fat diet in this study.

To compare performance levels, UB researchers placed subjects on three different diets for one
week each, and conducted exercise testing at the end of each week. The three diets were:

Six male members of the UB track team took part in the study. The athletes were tested on
treadmills after each week’s diet to determine maximum oxygen consumption -- a measure of the
efficiency of one’s oxygen-transport system and an indicator of aerobic capacity -- and

To eliminate any carry-over effect from the carbohydrate regimen, the runners consumed and were
tested on the higher-fat diet before the high- carbohydrate diet.

Results showed the athletes ran 20 percent longer on the high-fat diet than on the carbohydrate
diet, and 32 percent longer on the high-fat diet than on their normal diets.

Maximum oxygen consumption was 11.4 percent higher on the high-fat diet than on the high-
carbohydrate diet, results showed. ..."

High-Fat Diet Raises "Good Cholesterol" In Trained Runners January 21, 1997 <URL:http://www.buffalo.edu/news/fast-execute.cgi/article-

A citation:

"Athletes training on a high-fat diet have a healthier cholesterol profile than when they eat
the traditional low-fat, high-carbohydrate training diet and they do not gain weight or body fat
in the process, new data from researchers at the University at Buffalo have shown. The study,
thought to be the first to show this effect in women, has important implications for anyone who
puts in high running mileage for health purposes. It shows they may be blunting the benefits of
running by eating a diet too low in fat.

Previous results from the same study group of athletes showed that increasing dietary fat also
improves endurance performance.

The new results, reported in the January issue of Medicine and Science in Sports and Exercise,
show that trained male and female runners who consumed a diet composed of as much as 42 percent
fat had higher levels of high-density lipoproteins (HDL) in their blood than when on a diet of
only 16 percent fat. HDL is the form of cholesterol known to lower the risk of coronary heart
disease. LDL, or low-density lipoproteins, is known as the "bad cholesterol" because it has the
opposite effect.

The runners, who trained at least 35 miles a week, did not gain weight on the high-fat diet or
show an increase in any risk factors for coronary heart disease. ..."

Very-Low-Fat Diet May Compromise Immune Function, Increase Infection Rate in Trained Runners, UB
Study Finds. Saturday, May 22, 1999 <URL:http://www.buffalo.edu/news/fast-execute.cgi/article-
page.html?article=27530009> <URL:http://www.sciencedaily.com/releases/1999/05/990528004622.htm>


"Trained runners who severely limit the amount of fat in their diets may be suppressing their
immune system and increasing their susceptibility to infections and inflammation, a University
at Buffalo study has shown.

In findings presented here today (May 22, 1999) at the fourth International Society for
Exercise and Immunology Symposium, lead author Jaya T. Venkatraman, Ph.D., reported that
running 40 miles per week on a diet composed of approximately 17 percent fat compromised the
runners' immune response.

The medium and high-fat diets, composed of approximately 32 and 41 percent fat respectively,
left the immune system intact, and enhanced certain components, the findings showed.

"The data suggest that higher-fat diets may lower the proinflammatory cytokines, free radicals
and hormones, and may enhance the levels of anti-inflammatory cytokines," Venkatraman said.


"In general, moderate levels of exercise are known to enhance the immune system," said
Venkatraman. "But high-intensity exercise and endurance exercise produce excess levels of free
radicals, which may place stress on the immune system.

"Since we have shown that athletes perform better on a higher-fat diet than on a low-fat diet,
it was important to determine if the higher-fat diet would further compromise the immune
system," she said. "We found that it did not, but the very-low-fat diet did."

The study involved six female and eight male competitive runners who trained at 40 miles a week
and were part of a larger performance study. They spent a month on their normal diets, followed
by a month each on diets composed of approximately 17 percent, 32 percent and 41 percent fat.
Protein remained stable at 15 percent and carbohydrates made up the difference.

The immune status of the runners was obtained by analyzing concentrations of essential
components of the immune system -- leukocytes, cytokines and plasma cortisol -- in blood samples
taken before and after an endurance exercise test. The tests were conducted at the end of each
four-week diet period.

Results showed that natural killer cells, a type of leukocyte and one of the body's defense
mechanisms marshaled to fight infection, were more than doubled in runners after the high-
fat diet, compared to the low-fat regimen. Levels of PGE2, inflammation-causing
prostaglandins, increased after the endurance test and were higher when the runners were on
the low-fat diet. ... "


1: Vogt M, Puntschart A, Howald H, Mueller B, Mannhart C, Gfeller-Tuescher L, Mullis P, Hoppeler
H. Effects of dietary fat on muscle substrates, metabolism, and performance in athletes. Med
Sci Sports Exerc. 2003 Jun;35(6):952-60. PMID: 12783043 [PubMed - indexed for MEDLINE] <URL:-

2: Roltsch MH, Flohr JA, Brevard PB. The effect of diet manipulations on aerobic performance. Int
J Sport Nutr Exerc Metab. 2002 Dec;12(4):480-9. PMID: 12500991 [PubMed - indexed for MEDLINE]

3: Burke LM, Hawley JA. Effects of short-term fat adaptation on metabolism and performance of
prolonged exercise. Med Sci Sports Exerc. 2002 Sep;34(9):1492-8. Review. PMID: 12218744 [PubMed
- indexed for MEDLINE] <URL:http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubM-

4: Helge JW. Long-term fat diet adaptation effects on performance, training capacity, and fat
utilization. Med Sci Sports Exerc. 2002 Sep;34(9):1499-504. Review. PMID: 12218745 [PubMed -
indexed for MEDLINE] <URL:http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed-

5: Burke LM, Hawley JA, Angus DJ, Cox GR, Clark SA, Cummings NK, Desbrow B, Hargreaves M.
Adaptations to short-term high-fat diet persist during exercise despite high carbohydrate
availability. Med Sci Sports Exerc. 2002 Jan;34(1):83-91. PMID: 11782652 [PubMed - indexed for
MEDLINE] <URL:http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1-

6: Venkatraman JT, Pendergast DR. Effect of dietary intake on immune function in athletes. Sports
Med. 2002;32(5):323-37. Review. PMID: 11929359 [PubMed - indexed for MEDLINE] <URL:http://www.-

7: Venkatraman JT, Feng X, Pendergast D. Effects of dietary fat and endurance exercise on plasma
cortisol, prostaglandin E2, interferon-gamma and lipid peroxides in runners. J Am Coll Nutr.
2001 Oct;20(5):529-36. PMID: 11601568 [PubMed - indexed for MEDLINE]

8: Carey AL, Staudacher HM, Cummings NK, Stepto NK, Nikolopoulos V, Burke LM, Hawley JA. Effects
of fat adaptation and carbohydrate restoration on prolonged endurance exercise. J Appl Physiol.
2001 Jul;91(1):115-22. PMID: 11408421 [PubMed - indexed for MEDLINE]

9: Lambert EV, Goedecke JH, Zyle C, Murphy K, Hawley JA, Dennis SC, Noakes TD. High-fat diet
versus habitual diet prior to carbohydrate loading: effects of exercise metabolism and cycling
performance. Int J Sport Nutr Exerc Metab. 2001 Jun;11(2):209-25. PMID: 11402254 [PubMed -
indexed for MEDLINE] <URL:http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed-

10: Lukaski HC, Bolonchuk WW, Klevay LM, Milne DB, Sandstead HH. Interactions among dietary fat,
mineral status, and performance of endurance athletes: a case study. Int J Sport Nutr Exerc
Metab. 2001 Jun;11(2):186-98. PMID: 11402252 [PubMed - indexed for MEDLINE] <URL:http://www.nc-

11: Coyle EF, Jeukendrup AE, Oseto MC, Hodgkinson BJ, Zderic TW. Low-fat diet alters intramuscular
substrates and reduces lipolysis and fat oxidation during exercise. Am J Physiol Endocrinol
Metab. 2001 Mar;280(3):E391-8. PMID: 11171592 [PubMed - indexed for MEDLINE]

12: Burke LM, Angus DJ, Cox GR, Cummings NK, Febbraio MA, Gawthorn K, Hawley JA, Minehan M, Martin
DT, Hargreaves M. Effect of fat adaptation and carbohydrate restoration on metabolism and
performance during prolonged cycling. J Appl Physiol. 2000 Dec;89(6):2413-21. PMID: 11090597
[PubMed - indexed for MEDLINE] <URL:http://jap.physiology.org/cgi/content/full/89/6/2413>

13: Helge JW. Adaptation to a fat-rich diet: effects on endurance performance in humans. Sports
Med. 2000 Nov;30(5):347-57. Review. PMID: 11103848 [PubMed - indexed for MEDLINE] <URL:http://-

14: Venkatraman JT, Leddy J, Pendergast D. Dietary fats and immune status in athletes: clinical
implications. Med Sci Sports Exerc. 2000 Jul;32(7 Suppl):S389-95. Review. PMID: 10910295
[PubMed - indexed for MEDLINE] <URL:http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve-

15: Pendergast DR, Leddy JJ, Venkatraman JT. A perspective on fat intake in athletes. J Am Coll
Nutr. 2000 Jun;19(3):345-50. Review. PMID: 10872896 [PubMed - indexed for MEDLINE]

16: Kern M, Lagomarcino ND, Misell LM, Schuster V V. The effect of medium-chain triacylglycerols on
the blood lipid profile of male endurance runners(1). J Nutr Biochem. 2000 May 1;11(5):288-292.
PMID: 10876103 [PubMed - as supplied by publisher] <URL:http://www.ncbi.nlm.nih.gov/entrez/que-

17: Horvath PJ, Eagen CK, Fisher NM, Leddy JJ, Pendergast DR. The effects of varying dietary fat on
performance and metabolism in trained male and female runners. J Am Coll Nutr. 2000 Feb;19(1):52-
60. PMID: 10682876 [PubMed - indexed for MEDLINE]

18: Goedecke JH, Christie C, Wilson G, Dennis SC, Noakes TD, Hopkins WG, Lambert EV. Metabolic
adaptations to a high-fat diet in endurance cyclists. Metabolism. 1999 Dec;48(12):1509-17.
PMID: 10599981 [PubMed - indexed for MEDLINE] <URL:http://www.ncbi.nlm.nih.gov/entrez/query.fc-

19: Pitsiladis YP, Smith I, Maughan RJ. Increased fat availability enhances the capacity of trained
individuals to perform prolonged exercise. Med Sci Sports Exerc. 1999 Nov;31(11):1570-9. PMID:
10589859 [PubMed - indexed for MEDLINE] <URL:http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd-

20: Hoppeler H, Billeter R, Horvath PJ, Leddy JJ, Pendergast DR. Muscle structure with low- and high-
fat diets in well-trained male runners. Int J Sports Med. 1999 Nov;20(8):522-6. PMID: 10606215
[PubMed - indexed for MEDLINE] <URL:http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&-

21: Hyyppa S, Saastamoinen M, Reeta Poso A. Effect of a post exercise fat-supplemented diet on
muscle glycogen repletion. Equine Vet J Suppl. 1999 Jul;30:493-8. PMID: 10659306 [PubMed -
indexed for MEDLINE] <URL:http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed-

22: Pogliaghi S, Veicsteinas A. Influence of low and high dietary fat on physical performance in
untrained males. Med Sci Sports Exerc. 1999 Jan;31(1):149-55. PMID: 9927023 [PubMed - indexed
for MEDLINE] <URL:http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_ui-

23: Brown RC, Cox CM. Effects of high fat versus high carbohydrate diets on plasma lipids and
lipoproteins in endurance athletes. Med Sci Sports Exerc. 1998 Dec;30(12):1677-83. PMID:
9861599 [PubMed - indexed for MEDLINE] <URL:http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=-

24: Venkatraman JT, Pendergast D. Effects of the level of dietary fat intake and endurance exercise
on plasma cytokines in runners. Med Sci Sports Exerc. 1998 Aug;30(8):1198-204. PMID: 9710857
[PubMed - indexed for MEDLINE] <URL:http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve-

25: Hawley JA, Brouns F, Jeukendrup A. Strategies to enhance fat utilisation during exercise.
Sports Med. 1998 Apr;25(4):241-57. Review. PMID: 9587182 [PubMed - indexed for MEDLINE] <URL-

26: Helge JW, Wulff B, Kiens B. Impact of a fat-rich diet on endurance in man: role of the dietary
period. Med Sci Sports Exerc. 1998 Mar;30(3):456-61. PMID: 9526894 [PubMed - indexed for
MEDLINE] <URL:http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9-

27: Lambert EV, Hawley JA, Goedecke J, Noakes TD, Dennis SC. Nutritional strategies for promoting
fat utilization and delaying the onset of fatigue during prolonged exercise. J Sports Sci. 1997
Jun;15(3):315-24. PMID: 9232557 [PubMed - indexed for MEDLINE] <URL:http://www.ncbi.nlm.nih.go-

28: Venkatraman JT, Rowland JA, Denardin E, Horvath PJ, Pendergast D. Influence of the level of
dietary lipid intake and maximal exercise on the immune status in runners. Med Sci Sports
Exerc. 1997 Mar;29(3):333-44. PMID: 9139172 [PubMed - indexed for MEDLINE] <URL:http://www.ncb-

29: Leddy J, Horvath P, Rowland J, Pendergast D. Effect of a high or a low fat diet on
cardiovascular risk factors in male and female runners. Med Sci Sports Exerc. 1997 Jan;29(1):17-
25. PMID: 9000152 [PubMed - indexed for MEDLINE] <URL:http://www.ncbi.nlm.nih.gov/entrez/query-

30: Pendergast DR, Horvath PJ, Leddy JJ, Venkatraman JT. The role of dietary fat on performance,
metabolism, and health. Am J Sports Med. 1996;24(6 Suppl):S53-8. PMID: 8947430 [PubMed -
indexed for MEDLINE] <URL:http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed-

31: Muoio DM, Leddy JJ, Horvath PJ, Awad AB, Pendergast DR. R Effect of dietary fat on metabolic
adjustments to maximal VO2 and endurance in runners. Med Sci Sports Exerc. 1994 Jan;26(1):81-8.
PMID: 8133743 [PubMed - indexed for MEDLINE] <URL:http://www.ncbi.nlm.nih.gov/entrez/query.fcg-

Matti Narkia