You want to be lean, healthy, and long-lived. You also want to be fit.
If you’re an athlete, model, or bodybuilder, your job might even depend on your ability to stay lean and/or excel at sports.
You know that what and how much you eat are important for your goals.
You also know that there are no good or bad foods, and that some “junk food” is fine in moderation. However, you’re still not sure exactly what you should eat for most of your calories.
In this article, you’re going to learn what are considered the most scientifically supported principles of a healthy diet. How you apply these principles will depend on your goals, preferences, and tolerances, and it’s possible some of this won’t apply to you. These are general principles that work well for most people who want to be healthy, lean, fit, and long-lived.
1. Eat Mostly Whole, Minimally Processed, Nutrient Dense, Filling Foods
There are no “healthy” or “unhealthy” foods.
However, different foods have different pros and cons in different situations for different people.
We’ll loosely define “healthy” food as something that roughly fits these four criteria:
1. Higher in micronutrients and lower in calories relative to other foods.
Consuming foods higher in essential vitamins, minerals, and other potentially beneficial compounds such as antioxidants may reduce your risk of nutrient deficiencies over time.1,2 It might make it easier to reach your micronutrient needs without over-consuming calories.3,4
Not all high-calorie foods are “unhealthy,” but many of the ones that people tend to overeat are low in nutrients.
2. More filling, less palatable, and harder to overeat.
Foods that are less palatable, flavorful, and complex, and higher in fiber, water, and protein are generally harder to overeat than other foods.4-7 Eating most of your diet from foods like this will make it easier for you to control your calorie intake and maintain a lean body composition.8
3. Less refined, processed, and modified from its original state.
Foods that have been modified to contain less filling ingredients such as fiber, water, and protein, and more sugar, flour, and fat, are usually easier to overeat.8-10 These foods also tend to be lower in micronutrients.11 Foods that have been less processed are generally more filling and nutrient-dense. As we’ve discussed before, however, this doesn’t mean all processed foods are bad for you, or that all unprocessed foods are good.
4. Fewer ingredients that are unsafe at lower doses.
Some foods contain ingredients that may be damaging in larger amounts, even in an overall balanced diet, such as trans-fats. It’s still unclear if you should avoid all trans-fats, but at this point the research does suggest limiting them far more than other fat sources.12 You could also include preservatives, dyes, artificial flavors, and some other compounds in this category.
Keep in mind that the amounts of these compounds you consume on a daily basis are generally well below the levels that could potentially be harmful. Just don’t eat them in massive amounts.
Every food can be bad for you in excess. A more accurate definition of “health-food” would be a food that has a higher safe dose than most other foods.
Here’s an extreme and unrealistic example to illustrate this point:
You could eat as much meat and fibrous vegetables as you wanted and you’d probably be fine. You probably wouldn’t suffer any major health issues or get fat.
If you ate as much chocolate cake, cookies, and ice cream as you wanted, you might get fat and run into some health problems eventually — at least if you love chocolate cake and cookies as much as I do.
It’s not possible to define exactly what constitutes a “healthy” or “unhealthy” food, but there are some generally understood principles for why certain foods need to be limited more than others.
Now let’s get a little more detailed and look at some food groups that probably should form the base of your diet.
2. Eat a Variety of Fruits and Vegetables
If there’s one thing pretty much everyone can agree on, it’s that vegetables are good for you.
People who eat more fruits and vegetables generally have a lower risk of most chronic diseases such as cancer, heart disease, obesity, and diabetes.13-21 When people eat more fruits and vegetables, they also tend to have an easier time losing weight and are better at maintaining weight loss,13,20,22-24 though not all data has found this to be true.25
Many of the benefits of fruits and vegetables are probably due to their fiber content. Fiber improves your digestive health, nourishes your gut bacteria, helps you stay full, and often reduces blood sugar swings.26 Studies have shown that people who increase their fiber intake from whole foods or supplements generally end up healthier and leaner than people who don’t.20,26,27
Vegetables also have a number of other compounds that help contribute to their positive effects, such as antioxidants and micronutrients, so taking a fiber supplement probably won’t give you the same benefits.20,26
Here’s the problem. Most Americans don’t consume the recommended daily intake of fruits, vegetables, or fiber, all of which are pathetically low to begin with.28-30 People get the majority of their fruit from orange juice, and most of their vegetables from fried potatoes.28
As a general rule, try to eat at least 5-10 servings, or 400 grams, of fruits and vegetables per day.31,32 More is generally better. Whether you eat mostly fruit or vegetables doesn’t really matter because many of the things we consider “vegetables” are actually fruit, like zucchini and tomatoes. It’s kind of a dumb distinction, so just eat lots of plant matter that’s fairly low in calories and high in micronutrients and fiber.
Not all plants have the same nutrients or benefits, so eat a variety. You don’t need to eat every color of the rainbow every day, but cycle through a few different kinds of fruits and vegetables every now and then to make sure you’re getting a nice spectrum.
3. Eat Enough Quality Protein
Studies have repeatedly shown that eating enough protein is crucial for losing fat, staying full, optimizing your adaptations to training, and maintaining muscle mass caused by dieting or aging.33-37 It’s also essential for maintaining good cardiometabolic health, adequate bone strength, immune function, growth, and virtually every other bodily process.33,38-42
Most Americans already eat enough protein for basic health, but some people may still not eat enough relative to their goals.33 Strength and endurance training increases your protein needs — you won’t be as good an athlete if you don’t eat enough protein.43-50 Calorie restriction also increases your protein needs because your body is trying to cannibalize your muscle tissue. If you eat enough protein, you generally lose less muscle and more fat while dieting.51 This is even more true for athletes.44,52
The kind of protein you eat also matters, but you probably don’t need to worry about this. “High quality” proteins have higher levels of essential amino acids and branched chain amino acids.53 They also tend to be easier for you to digest and absorb.
The good news is that you’re probably already eating enough quality protein. The only people who are really at risk for not eating enough quality protein are those who are forced (or force themselves) to eat an extremely suboptimal diet with very few protein sources for long periods of time. For instance, if you’re a starving African child who gets 80 or 90 percent of your calories from wheat or corn, you’re probably not getting enough quality protein. The same thing is probably true for some vegans (though not all).
It’s possible that eating more quality protein may enhance satiety, glucose control, and have some other yet undiscovered benefits.33 However, you’re probably consuming enough for optimal health if you eat a fairly balanced diet and get your protein from a variety of plants and animals.
4. Eat a Variety of Animal Products
Technically, you could get enough quality protein only from plants. However, most plants don’t have all of the essential amino acids, which means you would have to be extremely careful to eat plants with the right amino acid levels.
Even if you were willing to go to this kind of trouble, there’s no scientific reason you should avoid animal products for your health. There are also some potential dangers of completely avoiding animal products and/or meat.
Animal products tend to be a much better source of branched chain amino acids and essential amino acids than plants. If you eat even a few servings of meat per day, you can be pretty sure you’re getting enough quality protein.
Animal products are also high in micronutrients and micro-minerals such as the more bioavailable form of heme-iron. Some nutrients are only available from animal products, like vitamin B12. Many animal products are also high in essential fatty acids, choline, retinol, antioxidants, and other nutrients. Animals also generally have higher levels of DHA and EPA, which are the fatty acids that seem to be the most important.
People who avoid animal products generally have a higher risk of becoming deficient in vitamin B12 and possibly several other nutrients.54-59 Interestingly, vegans also tend to be at a higher risk of developing advanced glycation end products, possibly as the result of not consuming enough of the amino acid carnosine.60,61
Given there’s little evidence animal products cause cancer, heart disease, or just about any other problem for most people, there’s really no reason not to eat them for health, leanness, or athletic performance. This doesn’t mean you should eat all of your calories from meat, but getting much of your protein and fat from a variety of animal products is a good way to ensure you’re getting adequate nutrition.
There are some vegetarians who are able to stay very healthy, but most still consume some animal products.
No matter how many minimally processed, whole, nutrient dense plants and animals you eat, however, you still need to understand one more principle.
5. Eat within Your Calorie and Macronutrient Needs
Calories count; macronutrients matter.
Your weight is determined by the difference between how many calories you consume and how many you expend. Given the massive health problems caused by obesity and overweight, managing your calorie intake is extremely important.
Maintaining a healthy weight reduces your risk of almost every known disease, and improves your quality and quantity of life.62,63
If your goal is to lose weight, you need to eat fewer calories than you expend.
If your goal is to gain weight, you need to eat more calories than you expend.
If your goal is to maintain your weight, you need to eat roughly the same amount of calories you expend, within a fairly narrow range over time.
This doesn’t necessarily mean you need to count calories, but that is one effective method for many people. Both the quality and quantity of your calorie intake matters, so focus on both.
You also need to make sure your macronutrient intake is aligned with your goals.
Protein is arguably the most important macronutrient, for the reasons we discussed a moment ago.
You also need to eat enough essential fatty acids to promote brain health, immune function, hormone formation, etc. However, your essential fatty acid needs are fairly small, and you can often get enough from a balanced diet.
Moderate fat diets also tend to do a better job of controlling hunger levels, and are often considered more palatable and sustainable by dieters in studies.35,64 Very low-fat diets also tend to decrease sex hormone levels and may also compromise immune function.65
Carbohydrate is not an essential macronutrient, meaning you won’t die without it. However, that doesn’t mean you should avoid it, either. Carbohydrate rich foods are often high in micronutrients and fiber, which studies have shown generally improve health. Very low carbohydrate diets may also cause a drop in thyroid levels over the long-term, and sometimes make people feel terrible (though this is obviously not true for everyone).66-68
For athletes who do more high intensity training, a higher carbohydrate intake is essential.69 After a certain point (roughly 80% of your maximum heart rate, give or take a little), your body uses primarily glycogen. No matter how long you decrease your carbohydrate intake and become “fat adapted,” your body will still need carbs to support high intensity training.70 All forms of strength training rely primarily on glycogen, which means if you’re lifting heavy, you need more carbs.
Higher carb diets may also be better if you’re dieting, especially if you’re pushing the limits of body composition. In these cases, high-carb diets tend to do a better job of supporting training intensity and recovery, minimizing the release of catabolic hormones, and maintaining leptin and thyroid levels.69,71-73 Anecdotally, many bodybuilding and endurance coaches also find that their athletes perform and feel better, recover faster, and get leaner on higher carb diets.
After making sure you’re eating enough protein, how much of your remaining calories come from carbohydrate or fat depends on your personal preferences, tolerances, and goals.
If you’re an athlete, you should probably eat more carbohydrate.
If you’re sedentary, you might want to eat less carbohydrate.
Some people do well on just about any diet as long as it has enough protein.
Extremes in any direction are generally not healthy, sustainable, or smart.
While there’s little evidence it’s unsafe, massively over-consuming protein is unnecessary. If it displaces too much carbohydrate or fat, it might also be detrimental.
Eating a very low-fat diet can decrease your immune function, recovery from workouts, and sex hormone levels.
Completely eliminating carbohydrate can work for some people, but it’s not usually necessary. For athletes, it’s often disastrous.
Eating way too much or not enough of any macronutrient also tends to increase the risk of nutrient deficiencies and cravings.
Here are some ballpark/default estimates for how much protein, fat, and carbohydrate you may want to eat. We’ll go into much more detail on these recommendations in later articles, but this should get you started.
Protein: 0.8-3.3 grams per kilogram of lean body mass.
Fat: >15% of total calories.
Carbohydrate: 20-75% of total calories.
Everything Else is Up to You
1. Eat Mostly Whole, Minimally Processed, Nutrient Dense, Satiating Foods
2. Eat a Variety of Fruits and Vegetables
3. Eat Enough Quality Protein
4. Eat a Variety of Animal Products
5. Eat within Your Calorie and Macronutrient Needs
Once you’ve mastered these five principles, the rest of your food choices depend on your preferences and tolerances.
Whether you eat grains, beans, bacon, spinach, blueberries, tree bark, or unicorn meat is your choice. In most cases, it doesn’t matter.
If you have a certain condition or disease such as diabetes, insulin resistance, thyroid problems, hypercholesterolemia, etc, you might need to avoid some foods. If there are certain foods you don’t like, then don’t eat them.
In the next article, we’ll look at how being more flexible about your diet can make you healthier, fitter, leaner, and happier.
What dietary principles do you use to stay healthy, lean, and fit?
Leave your thoughts in the comments section below.
1. Diaz JR, las Cagigas de A, Rodriguez R. Micronutrient deficiencies in developing and affluent countries. Eur J Clin Nutr. 2003;57 Suppl 1:S70–2.
2. Tontisirin K, Nantel G, Bhattacharjee L. Food-based strategies to meet the challenges of micronutrient malnutrition in the developing world. Proc Nutr Soc. 2002;61(2):243–250. doi:10.1079/PNS2002155.
3. Calton JB. Prevalence of micronutrient deficiency in popular diet plans. J Int Soc Sports Nutr. 2010;7:24. doi:10.1186/1550-2783-7-24.
4. Miller GD, Drewnowski A, Fulgoni V, Heaney RP, King J, Kennedy E. It is time for a positive approach to dietary guidance using nutrient density as a basic principle. J Nutr. 2009;139(6):1198–1202. doi:10.3945/jn.108.100842.
5. Appelhans BM, Woolf K, Pagoto SL, Schneider KL, Whited MC, Liebman R. Inhibiting food reward: delay discounting, food reward sensitivity, and palatable food intake in overweight and obese women. Obesity (Silver Spring). 2011;19(11):2175–2182. doi:10.1038/oby.2011.57.
6. Ello-Martin JA, Ledikwe JH, Rolls BJ. The influence of food portion size and energy density on energy intake: implications for weight management. Am J Clin Nutr. 2005;82(1 Suppl):236S–241S. Available at: http://ajcn.nutrition.org/content/82/1/236S.long.
7. Mela DJ. Determinants of food choice: relationships with obesity and weight control. Obes Res. 2001;9 Suppl 4:249S–255S. doi:10.1038/oby.2001.127.
8. Rebello CJ, Liu AG, Greenway FL, Dhurandhar NV. Dietary strategies to increase satiety. Adv Food Nutr Res. 2013;69:105–182. doi:10.1016/B978-0-12-410540-9.00003-X.
9. Gilhooly CH, Das SK, Golden JK, et al. Food cravings and energy regulation: the characteristics of craved foods and their relationship with eating behaviors and weight change during 6 months of dietary energy restriction. International Journal of Obesity (2005). 2007;31(12):1849–1858. doi:10.1038/sj.ijo.0803672.
10. Hill JO. Understanding and addressing the epidemic of obesity: an energy balance perspective. Endocr Rev. 2006;27(7):750–761. doi:10.1210/er.2006-0032.
11. Livingstone MBE, Rennie KL. Added sugars and micronutrient dilution. Obes Rev. 2009;10 Suppl 1:34–40. doi:10.1111/j.1467-789X.2008.00563.x.
12. Mozaffarian D, Aro A, Willett WC. Health effects of trans-fatty acids: experimental and observational evidence. Eur J Clin Nutr. 2009;63 Suppl 2:S5–21. doi:10.1038/sj.ejcn.1602973.
13. Alinia S, Hels O, Tetens I. The potential association between fruit intake and body weight–a review. Obes Rev. 2009;10(6):639–647. doi:10.1111/j.1467-789X.2009.00582.x.
14. Martin C, Zhang Y, Tonelli C, Petroni K. Plants, diet, and health. Annu Rev Plant Biol. 2013;64:19–46. doi:10.1146/annurev-arplant-050312-120142.
15. Boeing H, Bechthold A, Bub A, et al. Critical review: vegetables and fruit in the prevention of chronic diseases. Eur J Nutr. 2012;51(6):637–663. doi:10.1007/s00394-012-0380-y.
16. Hartley L, Igbinedion E, Holmes J, et al. Increased consumption of fruit and vegetables for the primary prevention of cardiovascular diseases. Cochrane Database Syst Rev. 2013;6:CD009874. doi:10.1002/14651858.CD009874.pub2.
17. Rees K, Dyakova M, Ward K, Thorogood M, Brunner E. Dietary advice for reducing cardiovascular risk. Cochrane Database Syst Rev. 2013;3:CD002128. doi:10.1002/14651858.CD002128.pub4.
18. Aune D, Chan DSM, Vieira AR, et al. Fruits, vegetables and breast cancer risk: a systematic review and meta-analysis of prospective studies. Breast Cancer Res Treat. 2012;134(2):479–493. doi:10.1007/s10549-012-2118-1.
19. Cooper AJ, Forouhi NG, Ye Z, et al. Fruit and vegetable intake and type 2 diabetes: EPIC-InterAct prospective study and meta-analysis. Eur J Clin Nutr. 2012;66(10):1082–1092. doi:10.1038/ejcn.2012.85.
20. Slavin JL. Position of the American Dietetic Association: health implications of dietary fiber. J Am Diet Assoc. 2008;108(10):1716–1731.
21. Cooper AJ, Sharp SJ, Lentjes MAH, et al. A prospective study of the association between quantity and variety of fruit and vegetable intake and incident type 2 diabetes. Diabetes Care. 2012;35(6):1293–1300. doi:10.2337/dc11-2388.
22. Liu S, Willett WC, Manson JE, Hu FB, Rosner B, Colditz G. Relation between changes in intakes of dietary fiber and grain products and changes in weight and development of obesity among middle-aged women. Am J Clin Nutr. 2003;78(5):920–927. Available at: http://ajcn.nutrition.org/content/78/5/920.long.
23. Brauchla M, Juan W, Story J, Kranz S. Sources of Dietary Fiber and the Association of Fiber Intake with Childhood Obesity Risk (in 2-18 Year Olds) and Diabetes Risk of Adolescents 12-18 Year Olds: NHANES 2003-2006. J Nutr Metab. 2012;2012:736258. doi:10.1155/2012/736258.
24. Champagne CM, Broyles ST, Moran LD, et al. Dietary intakes associated with successful weight loss and maintenance during the Weight Loss Maintenance trial. J Am Diet Assoc. 2011;111(12):1826–1835. doi:10.1016/j.jada.2011.09.014.
25. Ledoux TA, Hingle MD, Baranowski T. Relationship of fruit and vegetable intake with adiposity: a systematic review. Obes Rev. 2011;12(5):e143–50. doi:10.1111/j.1467-789X.2010.00786.x.
26. Anderson JW, Baird P, Davis RHJ, et al. Health benefits of dietary fiber. Nutr Rev. 2009;67(4):188–205. doi:10.1111/j.1753-4887.2009.00189.x.
27. Aune D, Chan DSM, Greenwood DC, et al. Dietary fiber and breast cancer risk: a systematic review and meta-analysis of prospective studies. Ann Oncol. 2012;23(6):1394–1402. doi:10.1093/annonc/mdr589.
28. Kimmons J, Gillespie C, Seymour J, Serdula M, Blanck HM. Fruit and vegetable intake among adolescents and adults in the United States: percentage meeting individualized recommendations. Medscape J Med. 2009;11(1):26.
29. King DE, Mainous AG3, Lambourne CA. Trends in dietary fiber intake in the United States, 1999-2008. J Acad Nutr Diet. 2012;112(5):642–648. doi:10.1016/j.jand.2012.01.019.
30. Clemens R, Kranz S, Mobley AR, et al. Filling America’s fiber intake gap: summary of a roundtable to probe realistic solutions with a focus on grain-based foods. J Nutr. 2012;142(7):1390S–401S. doi:10.3945/jn.112.160176.
31. Costain L, Croker H. Helping individuals to help themselves. Proc Nutr Soc. 2005;64(1):89–96.
32. Krolner R, Rasmussen M, Brug J, Klepp K-I, Wind M, Due P. Determinants of fruit and vegetable consumption among children and adolescents: a review of the literature. Part II: qualitative studies. Int J Behav Nutr Phys Act. 2011;8:112. doi:10.1186/1479-5868-8-112.
33. Layman DK. Protein quantity and quality at levels above the RDA improves adult weight loss. J Am Coll Nutr. 2004;23(6 Suppl):631S–636S. Available at: http://pmid.us/15640518.
34. Soenen S, Westerterp-Plantenga MS. Proteins and satiety: implications for weight management. Curr Opin Clin Nutr Metab Care. 2008;11(6):747–751.
35. Paddon-Jones D, Westman E, Mattes RD, Wolfe RR, Astrup A, Westerterp-Plantenga M. Protein, weight management, and satiety. Am J Clin Nutr. 2008;87(5):1558S–1561S. Available at: http://ajcn.nutrition.org/content/87/5/1558S.long.
36. Breen L, Phillips SM. Interactions between exercise and nutrition to prevent muscle waste during ageing. Br J Clin Pharmacol. 2013;75(3):708–715. doi:10.1111/j.1365-2125.2012.04456.x.
37. Halton TL, Hu FB. The effects of high protein diets on thermogenesis, satiety and weight loss: a critical review. J Am Coll Nutr. 2004;23(5):373–385. Available at: http://www.jacn.org/content/23/5/373.long.
38. Layman DK, Baum JI. Dietary protein impact on glycemic control during weight loss. J Nutr. 2004;134(4):968S–73S. Available at: http://jn.nutrition.org/content/134/4/968S.long.
39. Layman DK, Boileau RA, Erickson DJ, et al. A reduced ratio of dietary carbohydrate to protein improves body composition and blood lipid profiles during weight loss in adult women. J Nutr. 2003;133(2):411–417.
40. Bonjour J-P. Protein intake and bone health. Int J Vitam Nutr Res. 2011;81(2-3):134–142. doi:10.1024/0300-9831/a000063.
41. Kerstetter JE, O’Brien KO, Insogna KL. Low protein intake: the impact on calcium and bone homeostasis in humans. J Nutr. 2003;133(3):855S–861S. Available at: http://jn.nutrition.org/content/133/3/855S.full.
42. Guadagni M, Biolo G. Effects of inflammation and/or inactivity on the need for dietary protein. Curr Opin Clin Nutr Metab Care. 2009;12(6):617–622. doi:10.1097/MCO.0b013e32833193bd.
43. Tarnopolsky M. Protein requirements for endurance athletes. Nutrition. 2004;20(7-8):662–668.
44. Lambert CP, Frank LL, Evans WJ. Macronutrient considerations for the sport of bodybuilding. Sports Med. 2004;34(5):317–327.
45. Tarnopolsky MA, Gibala MJ, Jeukendrup AE, Phillips SM. Nutritional needs of elite endurance athletes. Part II: Dietary protein and the potential role of caffeine and creatine. European Journal of Sport Science. 2005;5(2):59–72. doi:10.1080/17461390500137485.
46. Kreider RB, Campbell B. Protein for exercise and recovery. Phys Sportsmed. 2009;37(2):13–21. doi:10.3810/psm.2009.06.1705.
47. Campbell B, Kreider RB, Ziegenfuss T, et al. International Society of Sports Nutrition position stand: protein and exercise. J Int Soc Sports Nutr. 2007;4:8. doi:10.1186/1550-2783-4-8.
48. Tipton KD, Wolfe RR. Protein and amino acids for athletes. J Sports Sci. 2004;22(1):65–79. doi:10.1080/0264041031000140554.
49. Wilson J, Wilson GJ. Contemporary issues in protein requirements and consumption for resistance trained athletes. J Int Soc Sports Nutr. 2006;3:7–27. doi:10.1186/1550-2783-3-1-7.
50. Rodriguez NR, Di Marco NM, Langley S. American College of Sports Medicine position stand. Nutrition and athletic performance. Med Sci Sports Exerc. 2009;41(3):709–731. Available at: http://www.medscape.com/viewarticle/717046.
51. Demling RH, DeSanti L. Effect of a hypocaloric diet, increased protein intake and resistance training on lean mass gains and fat mass loss in overweight police officers. Ann Nutr Metab. 2000;44(1):21–29.
52. Mettler S, Mitchell N, Tipton KD. Increased protein intake reduces lean body mass loss during weight loss in athletes. Med Sci Sports Exerc. 2010;42(2):326–337. doi:10.1249/MSS.0b013e3181b2ef8e.
53. Millward DJ, Layman DK, Tome D, Schaafsma G. Protein quality assessment: impact of expanding understanding of protein and amino acid needs for optimal health. Am J Clin Nutr. 2008;87(5):1576S–1581S. Available at: http://ajcn.nutrition.org/content/87/5/1576S.long.
54. Gilsing AMJ, Crowe FL, Lloyd-Wright Z, et al. Serum concentrations of vitamin B12 and folate in British male omnivores, vegetarians and vegans: results from a cross-sectional analysis of the EPIC-Oxford cohort study. Eur J Clin Nutr. 2010;64(9):933–939. doi:10.1038/ejcn.2010.142.
55. Herrmann W, Schorr H, Obeid R, Geisel J. Vitamin B-12 status, particularly holotranscobalamin II and methylmalonic acid concentrations, and hyperhomocysteinemia in vegetarians. Am J Clin Nutr. 2003;78(1):131–136. Available at: http://ajcn.nutrition.org/content/78/1/131.long.
56. Pawlak R, Parrott SJ, Raj S, Cullum-Dugan D, Lucus D. How prevalent is vitamin B(12) deficiency among vegetarians? Nutr Rev. 2013;71(2):110–117. doi:10.1111/nure.12001.
57. Davis BC, Kris-Etherton PM. Achieving optimal essential fatty acid status in vegetarians: current knowledge and practical implications. Am J Clin Nutr. 2003;78(3 Suppl):640S–646S. Available at: http://ajcn.nutrition.org/content/78/3/640S.full.
58. Obersby D, Chappell DC, Dunnett A, Tsiami AA. Plasma total homocysteine status of vegetarians compared with omnivores: a systematic review and meta-analysis. Br J Nutr. 2013;109(5):785–794. doi:10.1017/S000711451200520X.
59. Kornsteiner M, Singer I, Elmadfa I. Very low n-3 long-chain polyunsaturated fatty acid status in Austrian vegetarians and vegans. Ann Nutr Metab. 2008;52(1):37–47. doi:10.1159/000118629.
60. Sebekova K, Krajcoviova-Kudlackova M, Schinzel R, Faist V, Klvanova J, Heidland A. Plasma levels of advanced glycation end products in healthy, long-term vegetarians and subjects on a western mixed diet. Eur J Nutr. 2001;40(6):275–281.
61. Krajcovicova-Kudlackova M, Sebekova K, Schinzel R, Klvanova J. Advanced glycation end products and nutrition. Physiol Res. 2002;51(3):313–316.
62. Vucenik I, Stains JP. Obesity and cancer risk: evidence, mechanisms, and recommendations. Ann N Y Acad Sci. 2012;1271:37–43. doi:10.1111/j.1749-6632.2012.06750.x.
63. Burke GL, Bertoni AG, Shea S, et al. The impact of obesity on cardiovascular disease risk factors and subclinical vascular disease: the Multi-Ethnic Study of Atherosclerosis. Arch Intern Med. 2008;168(9):928–935. doi:10.1001/archinte.168.9.928.
64. Brehm BJ, Seeley RJ, Daniels SR, D’Alessio DA. A randomized trial comparing a very low carbohydrate diet and a calorie-restricted low fat diet on body weight and cardiovascular risk factors in healthy women. J Clin Endocrinol Metab. 2003;88(4):1617–1623. Available at: http://jcem.endojournals.org/content/88/4/1617.long.
65. Venkatraman JT, Leddy J, Pendergast D. Dietary fats and immune status in athletes: clinical implications. Med Sci Sports Exerc. 2000;32(7 Suppl):S389–95.
66. Mathieson RA, Walberg JL, Gwazdauskas FC, Hinkle DE, Gregg JM. The effect of varying carbohydrate content of a very-low-caloric diet on resting metabolic rate and thyroid hormones. Metab Clin Exp. 1986;35(5):394–398.
67. Serog P, Apfelbaum M, Autissier N, Baigts F, Brigant L, Ktorza A. Effects of slimming and composition of diets on VO2 and thyroid hormones in healthy subjects. Am J Clin Nutr. 1982;35(1):24–35. Available at: http://ajcn.nutrition.org/content/35/1/24.full.pdf.
68. Spaulding SW, Chopra IJ, Sherwin RS, Lyall SS. Effect of caloric restriction and dietary composition of serum T3 and reverse T3 in man. J Clin Endocrinol Metab. 1976;42(1):197–200.
69. Burke LM, Hawley JA, Wong SHS, Jeukendrup AE. Carbohydrates for training and competition. J Sports Sci. 2011;29 Suppl 1:S17–27. doi:10.1080/02640414.2011.585473.
70. Burke LM, Kiens B. “Fat adaptation” for athletic performance: the nail in the coffin? J Appl Physiol. 2006;100(1):7–8. doi:10.1152/japplphysiol.01238.2005.
71. Lane AR, Duke JW, Hackney AC. Influence of dietary carbohydrate intake on the free testosterone: cortisol ratio responses to short-term intensive exercise training. Eur J Appl Physiol. 2010;108(6):1125–1131. doi:10.1007/s00421-009-1220-5.
72. Jenkins AB, Markovic TP, Fleury A, Campbell LV. Carbohydrate intake and short-term regulation of leptin in humans. Diabetologia. 1997;40(3):348–351. doi:10.1007/s001250050686.
73. Burke LM, Kiens B, Ivy JL. Carbohydrates and fat for training and recovery. J Sports Sci. 2004;22(1):15–30. doi:10.1080/0264041031000140527.