The Modern Evolution of “Diet”

· Volume 5

A Notable Development in Medical Nutrition
Michael Long

diet (dahy-it), n. A regimen of eating followed for medical reasons, or in order to lose weight.

The Oxford English Dictionary1

The word diet is derived from the Greek diaita, which means “prescribed way of living,” specifically prescribed by a physician.2 An inherent sense of health and wellness is suggested in the historical use of the word. However, popular culture has developed a very different understanding of diet than thatwhich is indicated by the OED definition. We optimally supply our bodies with nutritive health-promoting fuel from our diets; ironically, we also restrict our bodies from nutritive health-promoting fuel when on a diet. This confusing dichotomy has dominated the nutrition headlines in the past decades. The connotations of diet have become transformed so that the concepts of health and diet are blurred and often misconstrued. If health is defined by the food we eat and if the food we eat is our diet, then seemingly reasonable logic tells us that dieting is healthy. This linguistic subtlety has inundated society, and despite an authentic attempt to maximize health, individuals may unintentionally diminish their health through the mere misunderstanding of a word.

It is no coincidence that the modern evolution of calorie-restricted diets are correlated with the rise of the ideal of slim body type, and with the greatest public health threat of our time, obesity.3 Any adaptation to the optimal human image opens a considerable niche of monetary gain for those involved in the weight loss industry. Proponents from every school of “fad diets” have their own rationale. Advocates of low-fat diets, popular in the 1980s and 1990s, attest that dietary fat should be restricted because excess calories are stored as fat.4 Supporters of low-carbohydrate diets, popular in the early 2000s, declare that their restriction forces the catabolism of alternative energy stores,5 presumably adipose, because carbohydrates are the predominant source of bodily energy,. A perusal through the multitude of weight loss regimens reveals restrictive variations of each macromolecule, including protein, lipid, and carbohydrate.

An understanding of the intricacies of the human metabolic process raises warning flags against harsh restriction of any nutritive class. Each macromolecule has essential functions; life would not be sustainable or possible without a threshold level of each one. The processes that allow interconversion between lipid, carbohydrate, and protein are well understood, but excessive need for conversion creates an intuitive energetic burden and suboptimal functionality. Extreme nutritive restrictions may not even fulfill the rudimentary goal of weight loss. Very low–fat diets barely outperform control diets and are considered clinically insignificant.6 Despite initial weight improvement with a lowcarbohydrate diet, weight change after 1 year is insignificant.7

Evidence of the harmfulness of weight loss diets is becoming apparent. Excessive fat restriction can cause deleterious health consequences, especially on the hormonal cascade, which is predominantly lipid based.8 Low-carbohydrate diets are even more problematic. They create a ketogenic (or starvation) state, which is linked with dehydration, fatigue, and bone density loss and neuropathy.9 Because synthesis of serotonin relies on the insulin-dependent uptake of tryptophan, a lowcarbohydrate diet is associated with dysthymia and depression.10 These findings—paired with knowledge that low-carbohydrate diets are generally low in fruits, vegetables, and fiber, while high in saturated and trans fats—mean that the protective effects of a healthy diet against cancer, cardiovascular disease, diabetes mellitus, and digestive disturbance are not elicited.

The goal of a fad diet is to maximally categorize the populace, as increased membership means increased wealth for diet distributors. Unfortunately, this is a gross simplification that completely discounts the individual. Each person functions uniquely at a microscopic level, with different energetic demands, allergic predispositions, and metabolic capacities. Therefore, a “one size fits all” approach to nutrition is ineffective. The core naturopathic principle of tolle totum (treat the whole person) is based on the understanding that the nutritive needs of each person are exclusive. Nutritional research is finally confirming what practitioners of nutritional medicine have known all along: eating largely positive nutritive indicators such as fruits, vegetables, and whole grains confers a favorable health status, whereas eating largely negative health indicators such as saturated or trans fats and simple sugars does not.11 Otherwise, optimal health is situational and highly dependent on factors such as age, sex, body size and type, preexisting medical conditions, and level of activity.

An unconscious reclaiming of the diet has begun in recent years. Consultations in optimal nutrition no longer focus on dietary restriction but rather on dietary balance. It is about empowering the individual and cordially inviting him or her to adopt a holistic and healthy lifestyle. Will forgoing refined sugar improve health? Surely. Is it sustainable? Definitely not. The most recent research in the field of medical nutrition indicates that it is the overall nutrition, not its individual components, that dictates the totality of health.12 That is, the whole is greater than the sum of the parts. This makes logical sense because focusing on individual components ignores the complex interactions occurring between them. From a functional standpoint, this could not be more obvious, as we do not eat isolated nutrients in the first place.

It is becoming acutely evident that swift intervention is needed to avert, or at least palliate, the long list of overnutrition and malnutrition confounders that are plaguing our population, including obesity, diabetes, cardiovascular disease, and cancer. Reframing a simple definition has potential to restructure the understanding of health. We can “diet” in an attempt to lose weight, despite our health, or we can challenge ourselves to embrace a healthy existence through the practical application of our diets. Scientific evidence has explicitly severed the connection between fad-dieting and health. An obvious and undeniable reassociation of the historical context of diet with health is needed. This can be accomplished by viewing diet not as a prescription for eating but as a wholesome and integrated regimen of life.



1. Simpson J, Weiner E. The Oxford English Dictionary. London, England: Oxford University Press; 2004.

2. Merriam-Webster, Inc. The Merriam-Webster New Book of Word Histories. London, England: Merriam-Webster; 1995.

3. Jeffery RW, Utter J. The changing environment and population obesity in the United States. Obes Res. 2003;11 (suppl):12S-22S.

4. Tarnower H. The Complete Scarsdale Medical Diet: Plus Dr. Tarnower’s Lifetime Keep-Slim Program. New York, NY: Bantam Books; 1982.

5. Atkins R. Dr. Atkins’ New Diet Revolution. Chicago, IL: Harper-Collins Publishers; 2001.

6. Pirozzo S, Summerbell C, Cameron C, Glasziou P. Advice on low-fat diets for obesity. Cochrane Database Syst Rev. 2002:CD003640.

7. Foster GD, Wyatt HR, Hill JO, et al. A randomized trial of low-carbohydrate diet for obesity. N Engl J Med. 2003;348:2082-2090.

8. Katan MB, Grundy SM, Willett WC. Should a low-fat, high-carbohydrate diet be recommended for everyone? beyond low-fat diets. N Engl J Med. 1997;337:563-567.

9. Tapper-Gardzina Y, Cotugna N, Vickery CE. Should you recommend a low-carb, high-protein diet? Nurse Pract. 2002;27:52-53, 55-56, 58-59.

10. Benton D. Carbohydrate ingestion, blood glucose and mood. Neurosci Biobehav Rev. 2002;26:293-308.

11. Serra-Majem L, Roman B, Estruch R. Scientific evidence of interventions using the Mediterranean diet: a systematic review. Nutr Rev. 2006;64:S27-S47.

12. Softi F, Cesari F, Abbate R, Gensini GF, Casini A. Adherence to Mediterranean diet and health status: meta-analysis. BMJ. 2008;337:a1344.