Tag Archives: Insulin
One prime example of this, is carbohydrates.3 One of the three main macronutrients, carbohydrates, especially the simple, man-made kind, are no doubt 21st-cenury man’s favorite dietary indulgence.4, 5 Do you crave broccoli? Hard to resist kale? I didn’t think so.6, 7, 8
However, replace the words “broccoli” and “kale” with “Reese’s Pieces” and “M&Ms” and we have a different situation altogether.9 The combination of sugar and fat, in just the right proportion (known in the food chemist field as ‘the bliss point’) is nigh-impossible to resist – quite literally.10, 11, 12 But even without the processed food industry, our brain handles carbohydrates in a very unique way.13, 14
Carbohydrates are either simple or complex.15 Whether they fall into one camp or the other, depends on their chemical structure.16 Simple carbs have one to two sugars, while complex carbohydrates contain three or more.17, 18 The standard dietary recommendation calls for 40-60% of your daily calories to come from carbohydrates.19 However, this is not a good idea.20, 21, 22, 23, 24
Our brain function’s dependency on carbohydrates is variable.25 Serotonin-releasing brain neurons are unique in the amount of neurotransmitter they release is normally controlled by food intake: carbohydrate consumption – acting via insulin secretion and the “plasma tryptophan ratio” – increases serotonin release; protein intake lacks this effect.26
This accounts for the “boost” we get when consuming carbs – and why we turn to them, day after day, to “make ourselves feel better,” after a long stressful day at work.27 Besides, the oft-repeated, anecdotal phrase “carbs make us fat,” stands up to science.28 In one study, a carbohydrate-restricted diet resulted in a significant reduction in fat mass and a concomitant increase in lean body mass in normal-weight men.29 Researchers posit this may be due to the reduced circulating insulin.30
Yet, many of the guiding sources for suggested carbohydrate intake for adults are at odds.34 This suggests very low-carbohydrate diets may not only be sustainable, but they may indeed be optimal.35, 36 Researchers point the likely finger at decreased transport of glucose across the brain, instead replaced by ketone bodies.37, 38
In some individuals, this can help with mental and behavioral detriments, such as obsessive-compulsive disorder and schizophrenia.39, 40, 41 Since the original “very low carbohydrate” diets were developed for treating epilepsy, this should come as no surprise.42
After eating carbohydrates, the level of the amino acid tryptophan in the brain goes up.43 This rise in brain tryptophan level follows from an increase in tryptophan transport into the brain, the consequence of an insulin-induced reduction in the blood levels of several amino acids that compete with tryptophan for brain uptake.44 This helps to explain, at least partially, why you may feel sleepy after a meal filled with large amounts of carbohydrates.45
One, as yet, untouched problem with carbohydrates and your brain, is an increased risk for dementia.46 Glycation is a big problem, and as sugar binds to protein in your body, you are now at an increased risk for developing dementia.47, 48, 49 What can you do to help control this? Quite simply, lower your carbohydrate intake.50 Instead, eat a diet rich in healthy fats, high in quality protein, and with enough quality carbohydrates to maintain activity levels.51, 52, 53 Quite simply, eat a Paleo Diet.
1. Leidy HJ, Lepping RJ, Savage CR, Harris CT. Neural responses to visual food stimuli after a normal vs. higher protein breakfast in breakfast-skipping teens: a pilot fMRI study. Obesity (Silver Spring). 2011;19(10):2019-25.
2. Cornier MA, Mcfadden KL, Thomas EA, et al. Differences in the neuronal response to food in obesity-resistant as compared to obesity-prone individuals. Physiol Behav. 2013;110-111:122-8.
3. Hevor TK. Some aspects of carbohydrate metabolism in the brain. Biochimie. 1994;76(2):111-20.
4. Siri PW, Krauss RM. Influence of dietary carbohydrate and fat on LDL and HDL particle distributions. Curr Atheroscler Rep. 2005;7(6):455-9.
5. Lavoie C. Gestational diabetes: poke, pee, and eat your carbs. Can Fam Physician. 2011;57(7):756-7, e239-40.
6. Imai S, Fukui M, Kajiyama S. Effect of eating vegetables before carbohydrates on glucose excursions in patients with type 2 diabetes. J Clin Biochem Nutr. 2014;54(1):7-11.
7. John JH, Ziebland S. Reported barriers to eating more fruit and vegetables before and after participation in a randomized controlled trial: a qualitative study. Health Educ Res. 2004;19(2):165-74.
8. Cordain L, Eaton SB, Sebastian A, et al. Origins and evolution of the Western diet: health implications for the 21st century. Am J Clin Nutr. 2005;81(2):341-54.
9. Gearhardt AN, Grilo CM, Dileone RJ, Brownell KD, Potenza MN. Can food be addictive? Public health and policy implications. Addiction. 2011;106(7):1208-12.
10. Gearhardt AN, Davis C, Kuschner R, Brownell KD. The addiction potential of hyperpalatable foods. Curr Drug Abuse Rev. 2011;4(3):140-5.
11. García-garcía I, Horstmann A, Jurado MA, et al. Reward processing in obesity, substance addiction and non-substance addiction. Obes Rev. 2014;
12. Davis C, Levitan RD, Kaplan AS, Kennedy JL, Carter JC. Food cravings, appetite, and snack-food consumption in response to a psychomotor stimulant drug: the moderating effect of “food-addiction”. Front Psychol. 2014;5:403.
13. Fernstrom JD, Wurtman RJ. Brain serotonin content: increase following ingestion of carbohydrate diet. Science. 1971;174(4013):1023-5.
14. Gómez-pinilla F. Brain foods: the effects of nutrients on brain function. Nat Rev Neurosci. 2008;9(7):568-78.
15. Englyst KN, Englyst HN. Carbohydrate bioavailability. Br J Nutr. 2005;94(1):1-11.
16. Cooper GM. The Cell: A Molecular Approach. 2nd edition. Sunderland (MA): Sinauer Associates; 2000. The Molecular Composition of Cells. Available from: //www.ncbi.nlm.nih.gov/books/NBK9879/
17. Varki A. Biological roles of oligosaccharides: all of the theories are correct. Glycobiology. 1993;3(2):97-130.
18. Roberts KM, Noble EG, Hayden DB, Taylor AW. Simple and complex carbohydrate-rich diets and muscle glycogen content of marathon runners. Eur J Appl Physiol Occup Physiol. 1988;57(1):70-4.
19. Peterson CM, Jovanovic-peterson L. Randomized crossover study of 40% vs. 55% carbohydrate weight loss strategies in women with previous gestational diabetes mellitus and non-diabetic women of 130-200% ideal body weight. J Am Coll Nutr. 1995;14(4):369-75.
20. Gardner CD, Kiazand A, Alhassan S, et al. 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. 2007;297(9):969-77.
21. Kowalski LM, Bujko J. [Evaluation of biological and clinical potential of paleolithic diet]. Rocz Panstw Zakl Hig. 2012;63(1):9-15.
22. Klonoff DC. The beneficial effects of a Paleolithic diet on type 2 diabetes and other risk factors for cardiovascular disease. J Diabetes Sci Technol. 2009;3(6):1229-32.
23. Jönsson T, Granfeldt Y, Ahrén B, et al. Beneficial effects of a Paleolithic diet on cardiovascular risk factors in type 2 diabetes: a randomized cross-over pilot study. Cardiovasc Diabetol. 2009;8:35.
24. O’dea K. Marked improvement in carbohydrate and lipid metabolism in diabetic Australian aborigines after temporary reversion to traditional lifestyle. Diabetes. 1984;33(6):596-603.
25. Turner CE, Byblow WD, Stinear CM, Gant N. Carbohydrate in the mouth enhances activation of brain circuitry involved in motor performance and sensory perception. Appetite. 2014;80:212-9.
26. Wurtman RJ, Wurtman JJ. Brain serotonin, carbohydrate-craving, obesity and depression. Obes Res. 1995;3 Suppl 4:477S-480S.
27. Lemmens SG, Martens EA, Born JM, Martens MJ, Westerterp-plantenga MS. Lack of effect of high-protein vs. high-carbohydrate meal intake on stress-related mood and eating behavior. Nutr J. 2011;10(1):136.
28. Sinitskaya N, Gourmelen S, Schuster-klein C, Guardiola-lemaitre B, Pévet P, Challet E. Increasing the fat-to-carbohydrate ratio in a high-fat diet prevents the development of obesity but not a prediabetic state in rats. Clin Sci. 2007;113(10):417-25.
29. Volek JS, Sharman MJ, Love DM, et al. Body composition and hormonal responses to a carbohydrate-restricted diet. Metab Clin Exp. 2002;51(7):864-70.
30. Slabber M, Barnard HC, Kuyl JM, Dannhauser A, Schall R. Effects of a low-insulin-response, energy-restricted diet on weight loss and plasma insulin concentrations in hyperinsulinemic obese females. Am J Clin Nutr. 1994;60(1):48-53.
31. Roberts RO, Roberts LA, Geda YE, et al. Relative intake of macronutrients impacts risk of mild cognitive impairment or dementia. J Alzheimers Dis. 2012;32(2):329-39.
32. Yaffe K, Blackwell T, Whitmer RA, Krueger K, Barrett connor E. Glycosylated hemoglobin level and development of mild cognitive impairment or dementia in older women. J Nutr Health Aging. 2006;10(4):293-5.
33. Crane PK, Walker R, Hubbard RA, et al. Glucose levels and risk of dementia. N Engl J Med. 2013;369(6):540-8.
34. Manninen AH. Metabolic effects of the very-low-carbohydrate diets: misunderstood “villains” of human metabolism. J Int Soc Sports Nutr. 2004;1(2):7-11.
35. Krebs NF, Gao D, Gralla J, Collins JS, Johnson SL. Efficacy and safety of a high protein, low carbohydrate diet for weight loss in severely obese adolescents. J Pediatr. 2010;157(2):252-8.
36. Galletly C, Moran L, Noakes M, Clifton P, Tomlinson L, Norman R. Psychological benefits of a high-protein, low-carbohydrate diet in obese women with polycystic ovary syndrome–a pilot study. Appetite. 2007;49(3):590-3.
37. Klepper J, Diefenbach S, Kohlschütter A, Voit T. Effects of the ketogenic diet in the glucose transporter 1 deficiency syndrome. Prostaglandins Leukot Essent Fatty Acids. 2004;70(3):321-7.
38. Paoli A, Bianco A, Damiani E, Bosco G. Ketogenic diet in neuromuscular and neurodegenerative diseases. Biomed Res Int. 2014;2014:474296.
39. Kraft BD, Westman EC. Schizophrenia, gluten, and low-carbohydrate, ketogenic diets: a case report and review of the literature. Nutr Metab (Lond). 2009;6:10.
40. Barañano KW, Hartman AL. The ketogenic diet: uses in epilepsy and other neurologic illnesses. Curr Treat Options Neurol. 2008;10(6):410-9.
41. O’rourke DA, Wurtman JJ, Wurtman RJ, et al. Aberrant snacking patterns and eating disorders in patients with obsessive compulsive disorder. J Clin Psychiatry. 1994;55(10):445-7.
42. Levy RG, Cooper PN, Giri P. Ketogenic diet and other dietary treatments for epilepsy. Cochrane Database Syst Rev. 2012;3:CD001903.
43. Spring B. Recent research on the behavioral effects of tryptophan and carbohydrate. Nutr Health. 1984;3(1-2):55-67.
44. Fernstrom JD. Carbohydrate ingestion and brain serotonin synthesis: relevance to a putative control loop for regulating carbohydrate ingestion, and effects of aspartame consumption. Appetite. 1988;11 Suppl 1:35-41.
45. Afaghi A, O’connor H, Chow CM. High-glycemic-index carbohydrate meals shorten sleep onset. Am J Clin Nutr. 2007;85(2):426-30.
46. Cukierman-yaffe T, Gerstein HC, Williamson JD, et al. Relationship between baseline glycemic control and cognitive function in individuals with type 2 diabetes and other cardiovascular risk factors: the action to control cardiovascular risk in diabetes-memory in diabetes (ACCORD-MIND) trial. Diabetes Care. 2009;32(2):221-6.
47. Sasaki N, Fukatsu R, Tsuzuki K, et al. Advanced glycation end products in Alzheimer’s disease and other neurodegenerative diseases. Am J Pathol. 1998;153(4):1149-55.
48. Münch G, Schinzel R, Loske C, et al. Alzheimer’s disease–synergistic effects of glucose deficit, oxidative stress and advanced glycation endproducts. J Neural Transm. 1998;105(4-5):439-61.
49. Takeuchi M, Yamagishi S. Possible involvement of advanced glycation end-products (AGEs) in the pathogenesis of Alzheimer’s disease. Curr Pharm Des. 2008;14(10):973-8.
50. Gasior M, Rogawski MA, Hartman AL. Neuroprotective and disease-modifying effects of the ketogenic diet. Behav Pharmacol. 2006;17(5-6):431-9.
51. Frassetto LA, Schloetter M, Mietus-synder M, Morris RC, Sebastian A. Metabolic and physiologic improvements from consuming a paleolithic, hunter-gatherer type diet. Eur J Clin Nutr. 2009;63(8):947-55.
52. Jönsson T, Granfeldt Y, Ahrén B, et al. Beneficial effects of a Paleolithic diet on cardiovascular risk factors in type 2 diabetes: a randomized cross-over pilot study. Cardiovasc Diabetol. 2009;8:35.
53. Lindeberg S, Jönsson T, Granfeldt Y, et al. A Palaeolithic diet improves glucose tolerance more than a Mediterranean-like diet in individuals with ischaemic heart disease. Diabetologia. 2007;50(9):1795-807.
Hello Dr. Cordain,
In your book The Paleo Answer you discuss how dairy products increase the insulin response in the body.
Do whey protein shakes do the same?
Thank you in advance,
Dr. Cordain’s Response:
Indeed whey protein is one of the key factors along with lactose in dairy products that likely causes insulin resistance. Two very recent studies show that whey protein consumed by body builders and athletes causes acne (see the citations and abstracts below).
Simonart T. Acne and Whey Protein Supplementation among Bodybuilders. Dermatology. 2012;225(3):256-8.
Accumulative evidence supports the role of nutritional factors in acne. I report here 5 healthy male adult patients developing acne after the consumption of whey protein, a favorite supplement of those engaged in bodybuilding. These observations are in line with biochemical and epidemiological data supporting the effects of milk and dairy products as enhancers of insulin/insulin-like growth factor 1 signaling and acne aggravation. Further prospective studies are required to determine the possible role of dietary supplements in the fitness and bodybuilding environment.
Silverberg NB. Whey protein precipitating moderate to severe acne flares in 5 teenaged athletes. Cutis. 2012 Aug;90(2):70-2.
Acne vulgaris has been linked to milk ingestion, both whole and skim milk. The milk fraction that promotes acne is unknown. Five case reports are presented of male patients aged 14 to 18 years who experienced onset of acne shortly after initiation of whey protein supplementation; 3 teenagers used the supplement for muscle building in football training and the other 2 for attempting to gain weight. All 5 patients had poor response to acne treatment regimens of oral antibiotics, topical retinoids, and benzoyl peroxide. Lesions fully cleared in 4 patients after discontinuation of whey protein supplementation, but 1 patient’s acne flared after reinitiation of the whey protein supplement. Two patients did not immediately discontinue whey protein supplementation; 1 of them cleared after he discontinued whey protein during his second course of isotretinoin and 1 was lost to follow-up. Among these patients, at least 6 different brands of whey protein supplementation had been used, including whey protein shakes and reconstituted powders. Whey protein may be the fraction of dairy products that promote acne formation. Larger studies are needed to determine the mechanism of comedogenesis.
Loren Cordain, Ph.D., Professor Emeritus