Q: Hi, the Paleo Diet makes a lot of sense to me and I very much appreciate the research that's gone into it. However, am I right in thinking that any diet we are adapted to may nevertheless not be an ideal diet? We adapted to a diet that enabled us to be healthy enough to live long enough to reproduce healthy enough offspring.
If I understand correctly, couldn't certain foods could make that basic diet even healthier? For example, I have The Paleo Diet for Atheletes out from the library right now and I see that you believe that the life of an athlete requires departure from a strict paleolithic diet. Couldn't properly treated grains and legumes be beneficial additions to the diet? (i.e. soaked/sprouted to reduce/eliminate anti-nutrients?)
I am waiting to receive The Paleo Diet from the library (I'm on a long waiting list, which is good news I guess!) so maybe you address this issue in the book, in which case, I apologise. But if not, I would appreciate knowing your views on soaking/sprouting grains and legumes, and the reasons behind those views.
Thanks so much,
Zena
A: Dear Zena, first of all - thanks for supporting our work.
We agree with your statement that sprouted/soaked legumes are healthier options rather than "normal" cooked legumes1, 2. When legumes are sprouted the seed germinates, and a shoot will emerge from it which is the part that it is eaten, and not the seed. Lectins are stored within the seed, and consequently they are not ingested when the sprout is eaten.
Nevertheless, another type of toxic/antinutritive compound - namely saponins - does exist in the sprouts, especially in legumes. Saponins have been shown to affect the gut barrier, and consequently the immune system function3. This may increase the risk of autoimmune disease in genetically susceptible individuals4.
As stated by Pusztai et al5, lectins are extremely heat stable, and cooking does not completely eliminate these toxic compounds. Therefore, to reduce their adverse effects, the best practice is to limit their intake.
On the other hand, a peptide fraction from the gluten proteins, namely gliadin, is found in wheat. Gliadin is resistant, at least, to digestive enzyme degradation6 and arrives intact when they come into contact with intestinal epithelial cells7 increasing intestinal permeability. I am not aware of any studies that have measured the effects of soaking/sprouting wheat, so until proper studies are done we cannot rule out the negative effects of gliadin.
While we can decrease the amount of antinutrients/toxins from legumes and grains by soaking/sprouting them, it seems like gliadin is more resistant to degradation - at least by digestive enzymes. However, this is only one part of the equation when it comes to the possible deleterious effects of consuming neolithic foods.
Having said that, in The Paleo Diet Dr. Cordain discusses the 85:15 rule, where he explains that eating 85% of the calories from modern paleolithic-like foods is still more healthy than the typical Western diet. In the typical Western diet, more than 70% of food calories comes from foods introduced in the human food chain after the agricultural revolution8. See Table 1.
Table 1. Food and food types found in Western diets generally unavailable to preagricultural hominins8
Food or food group Value (% of energy)
Dairy Products
Whole milk 1.6
Low-fat milk 2.1
Cheese 3.2
Butter 1.1
Other 2.6
Total 10.6
Cereal grains
Whole grains 3.5
Refined grains 20.4
Total 23.9
Refined sugars
Sucrose 8.0
High-fructose corn syrup 7.8
Glucose 2.6
Syrups 0.1
Other 0.1
Total 18.6
Refined vegetable oils
Salad, cooking oils 8.8
Shortening 6.6
Margarine 2.2
Total 17.6
Alcohol 1.4
Total Energy 72.1
Added salt, as sodium chloride 9.6
On the other hand, the more we deviate from our genetic makeup (the stone age diet) the more adverse the consequences of diet will be upon our metabolism.
Regarding nutrition for athletes, several key points must be considered:
1. Diet induced acidosis: as explained by Dr. Cordain in page 99 of his book The Paleo Diet for Athletes, all foods after digestion are processed by the kidneys as either acid or base. If one's diet produces a net acid load, the body’s allostatic systems will neutralize this effect using three mechanisms (buffering, increased ventilation, and increased reabsorption and generation of HCO3- by the kidneys). The buffering system will utilize either bone calcium salts or muscle glutamine stores to compensate for acidosis9. In case of calcium salts, an increased urine calcium excretion is seen in net acid producing diets. Muscle glutamine is a key substance for adequate muscle recovery, hence a net acid diet could reduce the glutamine pool, leading to decreased athletic performance, as well as the increased risk of fracture due to bone calcium salts being utilized by the buffer system9. Table 2 shows different foods and their potential acid or base loads (positive is acid producing and negative is base producing).
Table 2. Potential net acid (or base) loads of 17 food groups8.
Net acid load
mEq/418 kJ Net acid load
mEq/10 460 kJ Potassium
mEq/418 kJ Protein
g/418 kJ Protein
g/100 mEq potassium
Acid-producing foods
Fish (n =
14.6 398 8.1 16.8 207
Meat (n = 3) 12.4 342 7.6 18.4 242
Poultry (n = 2) 7.8 227 4.7 13.4 287
Egg (n = 1) 7.3 215 2.4 8.3 339
Shellfish (n = 3) 7.3 215 18.4 18.0 159
Cheese (n = 9) 3.3 115 0.8 7.1 982
Milk (n = 4) 1.3 64 6.4 5.7 90
Cereal grains (n = 7) 1.1 60 2.6 3.2 153
Near-neutral foods
Legumes (n = 6) -0.4 24 12.6 10.6 100
Base-producing foods
Nuts (n = 6) -1.1 6 3.8 2.5 86
Fresh fruit (n = 11) -5.2 -98 9.4 1.6 16
Tuber (n = 2) -5.4 -102 11.8 2.2 18
Mushrooms (n = 1) -11.2 -247 62.3 25.7 41
Roots (n = 5) -17.1 -395 34.3 6.8 21
Vegetables and fruit (n = 1) -17.5 -404 35.5 5.6 15
Leafy greens (n = 6) -23.4 -553 43.5 10.0 24
Plant stalks (n = 1) -24.9 -590 54.8 4.6 8
2. When consuming grains and legumes in greater quantities than vegetables and fruits, fewer micronutrients are ingested, leading to a possible micronutrient disequilibrium. This is because vegetables and fruits are more nutrient dense than grains (even whole grains)8. See Table 3. Some micronutrients are very important for proper muscle function: such as magnesium, calcium or zinc. Antioxidants also play a role in the recovery phase after exercise, decreasing oxidative stress, and hence inflammation10.
Table 3. Mean nutrient density of various food groups (418-kJ samples)8.
Whole grains
(n =
Whole milk
(n = 1) Fruit
(n = 20) Vegetables
(n = 18) Seafood
(n = 20) Lean meats
(n = 4) Nuts and seeds
(n = 10)
Vitamin B-12 (µg) 0.00[4] 0.58[5] 0.00[4] 0.00[4] 7.42[7] 0.63[6] 0.00[4]
Vitamin B-3 (mg) 1.12[4] 0.14[1] 0.89[3] 2.73[5] 3.19[6] 4.73[7] 0.35[2]
Phosphorous (mg) 90.00[3] 152.00[5] 33.00[1] 157.00[6] 219.00[7] 151.00[4] 80.00[2]
Riboflavin (mg) 0.05[2] 0.26[6] 0.09[3] 0.33[7] 0.09[3] 0.14[5] 0.04[1]
Thiamin (mg) 0.12[5] 0.06[1] 0.11[3] 0.26[7] 0.08[2] 0.18[6] 0.12[4]
Folate (µg) 10.30[4] 8.10[2] 25.00[6] 208.30[7] 10.80[3] 3.80[1] 11.00[5]
Vitamin C (mg) 1.53[3] 74.20[5] 221.30[7] 93.60[6] 1.90[4] 0.10[1] 0.40[2]
Iron (mg) 0.90[4] 0.08[1] 0.69[2] 2.59[7] 2.07[6] 1.10[5] 0.86[3]
Vitamin B-6 (mg) 0.09[3] 0.07[1] 0.20[5] 0.42[7] 0.19[4] 0.32[6] 0.08[2]
Vitamin A (RE) 2.00[2] 50.00[5] 94.00[6] 687.00[7] 32.00[4] 1.00[1] 2.00[3]
Magnesium (mg) 32.60[4] 21.90[2] 24.60[3] 54.50[7] 36.10[6] 18.00[1] 35.80[5]
Calcium (mg) 7.60[2] 194.30[7] 43.00[4] 116.80[6] 43.1[5] 6.10[1] 17.5[3]
Zinc (mg) 0.67[4] 0.62[3] 0.25[1] 1.04[5] 7.60[7] 1.90[6] 0.60[2]
Sum rank score 44.00 44.00 48.00 81.00 65.00 50.00 38.00
Food types within food groups are based on the most commonly consumed foods in the US diet. Values in brackets (7 = highest; 1 = lowest). The micronutrient concentrations for each food group were derived from reference 64 within the article cited as reference 8 in this article. RE = retinol equivalents.
3. Branched chain amino acids are crucial for optimal athletic performance. If you review Dr. Cordain’s explanation on page 53 of The Paleo Diet for Athletes, you’ll note the fact that eggs, meat, and seafood are the richest sources of the branched chain amino acids Leucine, Isoleucine and Valine. Therefore, by replacing these foods with grains or legumes, you might become BCAA deficient, and your athletic performance could be diminished.
Table 4. Branched chain amino acid (BCAA) content of selected food products.
Source (100 Calorie sample) Isoleucine (mg) Leucine (mg) Valine (mg) Total BCCA (mg)
Egg white powder 1200 1791 1352 4344
Egg white raw 1188 1774 1340 4302
Whey protein 922 1719 896 3538
Meats 928 1474 967 3369
Soy protein 886 1481 923 3291
Seafoods 744 1285 803 2832
Hard boiled egg 389 442 494 1327
Milk 323 524 358 1206
Beans 319 524 349 1193
Veggies 238 287 245 771
Grains 130 303 172 606
Nuts and seeds 111 198 149 459
Starchy root vegetables 45 66 58 169
Fruits 20 31 29 82
The bottom line is that our metabolism is perfectly adapted to the nutrition that shaped our genome during millions of years of evolution. However, we believe that athletes could do very well on a diet based on 85% paleolithic nutrients, which is still much better than the typical Western diet.
I hope this is helpful.
Maelán Fontes
References:
1. V. DHURANDHAR and K.C. CHANG. Effect of Cooking on Firmness, Trypsin Inhibitors, Lectins and Cystine/Cysteine content of Navy and Red Kidney Beans (Phaseolus vulgaris). JOURNAL OF FOOD SCIENCE-Volume 55, No. 2, 1990.
2. Alka Sharma and Salil Sehgal. Effect of processing and cooking on the antinutritional factors of faba bean (Viola faba). Food chemistry. 43 (1992) 383-5.
3. Patel B, Rober S, Sporns P, et al. potato glycoalkaloid adversely affect intestinal permeabiliry and aggravate inflammatory bowel disease.
4. Visser J, Rozing J, Sapone A et al. Tight junctions, Intestinal permeability and Autoimmunity. Ann. N. Y. Acad. Sci. 1165: 195-205 (2009).
5. Pusztai A and Grant G. Assessment of lectin inactivation by heat and digestion. From methos in molecular medicine. Vol 9 Lectin methods and protocols. Edited by J M Rhodes and J D Milton Humana Press Inc. Totowa, NJ.
6. Shan L, Qiao SW, Arentz-Hansen H, et al. Identification and Analysis of Multivalent Proteolytically Resistant Peptides from Gluten: Implications for Celiac Sprue. J Proteome Res. 2005 ; 4(5): 1732–1741.
7. Drago S, Asmar R, Di Pierro M, et al. Gliadin, zonulin and gut permeability: Effects on celiac and non-celiac intestinal mucosa and intestinal cell lines. Scandinavian Journal of Gastroenterology, 2006; 41: 408/419.
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;81:341–54.
9. Pizzorno J, Frassetto LA and Katzinger J. Diet-induced acidosis: is it real and clinically relevant? British Journal of Nutrition (2010), 103, 1185–1194.
10. Prostanoid and isoprostanoid pathways in atherogenesis. Praticó D. Atherosclerosis 201 (2008) 8–16.
