‘Clinical epidemiology’ is the application of rigorous logic and statistics to the study of diagnosis, prognosis, and therapy . ‘Evidence-based medicine’ provides a hierarchical framework for evaluating clinical evidence . The importance of the word, ‘clinical,’ cannot be overstated. ‘Clinic’ and ‘clinical’ refer to ‘doctors and patients,’ ‘the bedside’, ‘those hospitalized with sickness.’ Clinical research, therefore, is solely applicable to people (humans).
Historically, many clinical discoveries have been a result of the observation of something happening in one person: an anecdote. A control group or power calculation was not necessary when the first patient survived meningitis after receiving penicillin, or when insulin and cortisol were given to those with insulin deficiency or adrenal insufficiency. In instances of extraordinary technical achievements, uncontrolled research has led to renal dialysis to reduce uremia, and organ transplantation. Of course, initial descriptive studies are not sufficient to generalize to other individuals or create practice policies and guidelines. But they might represent the beginning of a fruitful line of research and clinical care.
Without access to the funding required to conduct expensive outcomes-based trials, the ‘state-of-the-art’ of the knowledge about carbohydrate restriction is not found by searching the published medical literature. Individuals and groups are organizing and studying themselves . The ‘state-of-the-art’ of carbohydrate restriction is found in self-experimentation, clinical practices, and independent research that crosses traditional disciplines.
In the paper by Dikeman (pp. 437–440), observations by physicians and patients with Type 1 diabetes mellitus have provided the pilot data to propose controlled clinical research. The paper by Reason (pp. 441–445) describes a group of individuals affected by an uncommon condition called McArdle's Disease who found improvement by using a carbohydrate-restricted diet. Now they are influencing the funded researchers of McArdle's Disease.
In the paper by Feltham (pp. 446–452), his n-of-1 self-experiment to address the time-honored belief that a “calorie is a calorie” resulted in dramatically different weight gain on diets with the same amount of calories, providing provocative pilot evidence that a calorie is NOT a calorie. In a similar fashion, the paper by Lake (pp. 453–462) shatters the notion that high levels of exercise can only be accomplished while consuming dietary carbohydrate: his group traveled 100 miles over 5 days on their own power while only consuming water.
CLINICAL PRACTICE REVIEWS
Translating randomized controlled trials into clinical practice is typically accomplished through outcomes studies or health services research. The paper by Foley (pp. 463–468) outlines the metabolic effects of carbohydrate-restricted dietary patterns, and how they could be integrated into disease prevention and/or treatment programs. In the papers by Unwin (pp. 469–479) and Mitchell (pp. 480–487), clinic data are reviewed to address one of the unsubstantiated concerns about low carbohydrate diets: impaired renal function. Panayotti (pp. 488–495) describes a clinical program that incorporates a carbohydrate-restriction dietary option in a Pediatric obesity program. In the paper by Oliver (pp. 496–502), a brief intervention using carbohydrate restriction led to weight loss in a clinical practice.
INDEPENDENT INTER-DISCIPLINARY RESEARCH
There is also a growing number of independent researchers who are facilitating the connections across disciplines exploring the possible use of carbohydrate-restricted diets. In the paper by O’Hearn (pp. 503–508), the potential for using a ketogenic diet for sleep disorders is reviewed.
The potential regarding carbohydrate-restricted dietary patterns for disease prevention and treatment is just beginning to be explored. It is my hope that the early investigations in this issue will be transferred from the ‘bedside’ to the ‘bench,’ and stimulate organizations that are interested in treating or preventing human illness to study or use carbohydrate-restricted dietary patterns.
Financial support and sponsorship
No financial support or sponsorship has been given.
Conflicts of interest
E.C.W. receives royalties for the sale of diet books, and has equity in Adapt Your Life, Inc., a company based on low-carbohydrate concepts.
REFERENCES AND RECOMMENDED READING
Papers of particular interest, published within the annual period of review, have been highlighted as:
▪ of special interest
▪▪ of outstanding interest
1. Feinstein AR. Clinical epidemiology: the architecture of clinical research. 1985; Philadelphia: W.B. Saunders Co, 812 p.
2. Straus SE, Glasziou P, Richardson WS, Haynes RB. Evidence-based medicine: how to practice and teach EBM. fifth editionEdinburgh London New York Oxford Philadelphia St. Louis Sydney: Elsevier; 2019; 324 p.
3. Lennerz BS, Barton A, Bernstein RK, et al. Management of Type 1 diabetes with a very low-carbohydrate diet. Pediatrics 2018; 141:e20173349.