Which are the best diets?
As a physician, I know that many of my patients would benefit from changes in lifestyle and diet. Attention to diet is of particular importance for those who are obese or overweight, and especially if they also have diabetes or pre-diabetes.
We should also be aware that dietary composition has important health effects that are independent of the effects on weight.?
Neither short term adherence to a restrictive weight-loss diet or treatment with GLP-1 agonists will lead to long term weight loss unless there is a long-term change in diet (and lifestyle). As physicians, we are remiss in our responsibilities if we don't guide our patients to a healthier diet as part of a healthier lifestyle. So which diets should we recommend? What diets help sustain weight loss and deliver long-term health benefits??
The literature on diets is extensive, but many studies with reported benefits are poorly controlled, use single blind interventions, have varying degrees of adherence, and show small effect size. However, there are well-designed studies that have shown some surprising benefits for people who are able to change to and sustain a healthy diet.
Types of diets
The major categories of diet are
A recent review describes each of these diet types and summarizes the known benefits [NEJM 2024].?Here is a concise summary of the diets that are shown to have health benefits:
Mediterranean diet
Perhaps the most studied of the plant-based diets is the Mediterranean diet, which has been shown in multiple studies to improve health outcomes. It consists of olives, cereal grains, pulses (edible seeds from legumes), fruits (the typical after-dinner dessert), vegetables, and herbs, together with limited quantities of goat meat, milk, game, and fish. Bread (whole-grain, made of barley, wheat, or both) has a predominant role at each meal, and olive oil accounts for a relatively large proportion of energy intake.?
Meta-analysis of multiple studies has demonstrated that this diet decreases rates of overall mortality, cardiovascular diseases, coronary heart disease, myocardial infarction, overall cancer incidence, neurodegenerative diseases and diabetes. [Eur J Clin Nutr 2018]
A more recent study of the Mediterranean diet followed 25,315 U.S. women for a mean duration of 24.7 years. It compared low and high adherence groups within the study, to show that greater adherence to the Mediterranean diet was associated with a 23% relative risk reduction in all-cause mortality. This mortality reduction was associated with improvements in multiple cardiometabolic factors, but was not associated with levels of total cholesterol, LDL-C, Lp(a), or HbA1c. [JAMA Network Open 2024]??
Another recent study of 110,799 UK residents who were followed for 9.4 years tracked their adherence to a Mediterranean lifestyle, which they assessed with the MEDLIFE index (a combination of questionnaire and dietary assessments of (1) Mediterranean food consumption, (2) Mediterranean dietary habits, and (3) physical activity, rest, social habits, and conviviality.) Increasing adherence to the Mediterranean lifestyle was associated with a reduction of all-cause mortality from 11% to 22%.? [Mayo Clinic proceedings 2024]
Vegetarian and low-fat diets
The Ornish diet is a well-known very low-fat vegetarian diet that has shown remarkable benefits in those who have severe atherosclerosis and established coronary heart diseas. It has been linked to a reduced risk of cardiovascular diseases, ischemic heart disease and death from ischemic heart disease, dyslipidemia, diabetes, certain types of cancer, and potentially, death from any cause. [Ornish 2008]
Other variations on vegetarian diets allow for a less strict restriction on fat content, and may be combined with dairy or even pescatarian components. These diets also have similar benefits. Any version of a strict vegetarian diet (including the vegan diet) will cause vitamin B12 deficiency, and may also lead to B2, niacin, iodine, zinc, calcium, potassium and selenium deficiencies. Thus, vitamin and mineral supplements are important for people on these diets. [NEJM 2024]
Carbohydrate-restricted (keto) diets
Carbohydrate restriction diets lead to measurable ketones in the blood. The very low carbohydrate diets include the 4:1 diet, which has 4 times as many calories from fat as from both protein and carbohydrate combined, and only 5% of all calories from carbohydrates. Another is the modified Atkins diet, which achieves 1:1 ratio with 10% of calories from carbohydrates. It too is ketogenic
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Many other popular diets are “low carbohydrate”, with less than 40% of calories from carbohydrates (EG, Zone and South Beach diets).
Ketogenic diets are effective at weight loss, and appear to reduce multiple cardiac risk factors (LDL cholesterol, fasting glucose and HbA1C), and may also have anticonvulsant benefits that can be helpful for treating drug-resistant seizure disorders. Keto diets also help suppress appetite, improve lipid profiles, improve insulin sensitivity, and reduce symptoms of polycystic ovarian syndrome (PCOS). [NEJM 2024]
Paleolithic diets
The Paleo diet is a low glycemic index diet that is intended to mimic the food consumption patterns of humans prior to 8500 BC. It includes vegetables, fruits, lean meat, fish, nuts, and eggs; it excludes grains or cereals, dairy products, legumes, added sugar and salt, and re- fined fats. Although the literature is not as extensive as for other diets, it does appear that the Paleo diet may be associated with improved glucose tolerance, insulin sensitivity and LDL cholesterol in patients with type 2 DM. [J Clin Med 2020]
DASH diet
The DASH, or Dietary approaches to stop hypertension diet consists of fruit and vegetables, and low-fat dairy products. It has high fiber and low fat content, with low saturated fats and low cholesterol
This diet was shown to reduce blood pressure by 5.5 mmHg systolic and 3.0 mm Hg diastolic, to be helpful for weight loss, and to improve insulin levels, HbA1C, and LDL cholesterol. Large trials and meta-analyses have demonstrated benefits of a decreased incidence of cardiovascular disease, coronary heart disease, stroke, and metabolic diseases such as diabetes. [NEJM 2024]
MIND diet
The MIND diet is a Mediterranean-DASH combined being studied for its ability to delay loss of cognitive function. Early studies are promising. The MIND diet appears to slow cognitive decline with aging [Alzheimer’s Dement.]
Time-restricted diets?(AKA Intermittent fasting)
Diets based on time have a long history and many cultural or religious associations. Examples include fasting for 16 hours each day, fasting for 2 days per week, fasting for 24 hours every other day, eating just one meal per day, fasting for 36 hours at a time, or simply choosing occasionally to skip meals.
If the diet reduces overall caloric intake, it will lead to weight loss and its associated benefits. Other benefits are possible, but to date these diets have not shown clear health benefits in human trials. [NEJM 2024]
Summary
I agree with the authors of the NEJM diet-review article who suggest "...advice on healthy eating should be incorporated into clinical practice and taught in medical curricula, and health care professionals should propose variations of plant-based diets by considering individual preferences, cost, affordability, and cultural issues."
Do you believe doctors and other healthcare providers should advise their patients about which type of diet they recommend??Let us know in this one-question survey!
References:??
P.S.? The phrase "You are what you eat" is often attributed to the French lawyer and gastronome Jean pescatarian Brillat-Savarin, who wrote in 1826, "Tell me what you eat and I will tell you what you are" ("Dis-moi ce que tu manges, je te dirai ce que tu es") in his book "Physiologie du Go?t" ("The Physiology of Taste").
Founder & CEO at OSP specializing in futuristic healthcare solutions
8 个月Great question! Geoffrey Rutledge It's essential for doctors to consider individual patient needs when recommending diets. Personalized nutrition can lead to better health outcomes. Diets like the Mediterranean, DASH, and plant-based diets have shown significant benefits for heart health and chronic disease management. Excited to read your review!
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8 个月Diets are great. The challenges are: 1) in educating on the complexity of the multivariate balances required to be met for adherence, 2) providing a tool to (accurately) assess adherence, 3) having that same tool provide food recommendations aligned with any chosen dietary pattern to help move the patient closer to adherence. Luckily, the FRESH Platform has already built the framework to do all 3, with a prototype for the high-carb DASH diet (there are 2 other DASH iterations with variable health effects) ready to roll. Let me know what’s needed to start getting referrals and more feedback to make improvements.
Love this - food is health.