Low Calorie, Low Fat, Low Carb, Mediterranean: What is the Best Diet for Weight Loss?

A Message from Dr. Christopher Still

Christopher Still, DO, FACN, FACP, Co-Clinical Editor, Bariatric Times; Medical Director for the Center for Nutrition and Weight Management, and Director for Geisinger Obesity Research Institute, Geisinger Medical Center, Danville, Pennsylvania. Dr. Still is also a board member of the Obesity Action Coalition, Tampa, Florida.

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Dear Colleagues,
No matter where I go, I find that people always want to know the answers to the following questions: 1) What is the best medication or supplement for weight loss? and 2) What is the best diet for weight loss? I provide the same answer to both questions—“It depends.”

As discussed in previous editorial messages, there are now multiple safe and effective medications and therapies approved for obesity treatment. There are many considerations in choosing the “right” medication for the “right” patient, and perhaps I will tackle that in a future editorial.

For now, I want to discuss the question of diet. There are a lot of different diets out there. Popular diets include the following: 1) low-calorie diet, which usually is defined as less than 1,000 calories per day, and limits a patient’s daily caloric intake based on age, weight, and activity level; 2) low-fat diet where typically less than 40g of fat is consumed per day; 3) low-carbohydrate diet where patients limit grains, starchy vegetables and fruit, and emphasize foods high in protein and fat; 4) the Mediterranean diet, which is rich in monounsaturated fat (MUFA) and also emphasizes vegetables, nuts, and legumes, and 5) commercial diets, such as Jenny Craig, Weight Watchers, and Nutrisystem.

Multiple clinical trials[1–3] have put these and other diets to the test. While some have found slight differences in weight loss among diets in the short term, they have all seemed to arrive at similar conclusions—caloric restriction by approximately 500 calories per day and sustained adherence are the key predictors of successful weight loss and maintenance. The larger, randomized clinical trials found strong and consistent evidence that when calorie intake is modestly reduced, macronutrient proportion of the diet (protein, carbohydrate, or fat) is NOT related to losing weight.

While calorie reduction and adherence are key, there were a couple of smaller studies published last year that showed interesting results. In patients that carry their weight in their mid-section—android or apple shape type of weight distribution—a Mediterranean meal plan was found to be superior. Garaulet et al[4] published that the Mediterranean diet showed improved weight loss and reduced cardiometabolic risk-related parameters after one year. This android type of weight distribution, which is predominately visceral fat, is known to be associated with insulin resistance, metabolic syndrome and other comorbid medical problems, such as diabetes, obstructive sleep apnea, and fatty liver disease. A MUFA-rich diet, like that of the Mediterranean diet, has been shown to improve insulin sensitivity.[4,5] So, in addition to a patient’s BMI, how a patient carries his or her weight is an important factor for risk stratification and possibly different treatment recommendations.

In order to prescribe a 500-calorie per day reduction meal plan, we first need to calculate how many calories the patient is consuming to maintain their current weight upon seeing you. Although there are many methods available for determining the total caloric intake of a patient (e.g., indirect calorimetry, Harris Benedict equation, World Health Organization [WHO] equation), I elect to use a simple calculation by multiplying the patient’s weight by 8 cal/pound in women and 10 cal/pound in men. Using this simple calculation you can determine the estimated total amount of calories the patient is consuming and then reduce by 500 calories. For example, if Mrs. Snow weighs 250 pounds you can conclude that 2,000 calories per day will maintain her weight. Reducing then by 500 calories will mean recommending her intake be 1,500 calories per day. If Mr. Snow weight 300 pounds, you would then recommend 2,500 calories per day for him (10 cal/pound x 300 pounds minus 500 calories= 2,500 calories per day).

After recommending a specific meal plan and calorie recommendation that I feel will be realistic for that patient, I often refer them to a dietitian. They do not have to see a registered dietitian, you can instruct them yourself, but I feel it is optimal for patients to see an RD if available to you. Patients may also be referred to the commercial weight loss programs, such as Jenny Craig, Weight Watchers, and Nutrisystem.
The second important factor in weight loss and maintenance is adherence to the specific meal plan and physical activity. This adherence can be facilitated by a variety of self-monitoring tools for increased accountability. Tools such as face-to-face weekly meetings, diet and physical activity logs, digital tracking devices, and APPs exist to help the patient maintain a routine and accountability. Moreover, internet delivered programs can also offer an effective option. Successful internet programs that provide weekly e-mail feedback to participants can induce weight losses of ~ 2/3 of those achieved by traditional on-site, face-to-face behavioral programs.[6]

In summary, when evaluating a patient for a specific meal and physical activity plan, remember that it is not “one size fits all.” While one diet may have been successful in one patient, it may prove unsuccessful in another similar patient for a multitude of reasons. Sometimes finding the right plan takes trial and error. When working with your patients, remember to help them focus on realistic goals and finding a routine that is just right for them.

Sincerely,
Christopher Still, DO, FACN, FACP

References
1.    Foster GD, Wyatt HR, Hill JO, et al. Weight and metabolic outcomes after 2 years on a low-carbohydrate versus low-fat diet: a randomized trial. Ann Intern Med. 2010;153(3):147–157.
2.    Bazzano LA, Hu T. Effects of low-carbohydrate and low-fat diets. Ann Intern Med. 2015;162(5):393.
3.    Dansinger ML, Gleason JA, Griffith JL. Comparison of the Atkins, Ornish, Weight Watchers, and Zone diets for weight loss and heart disease risk reduction: a randomized trial. JAMA. 2005;293(1):43–53.]
4.    Garaulet M, Hernandez-Morante JJ, et al. Relation between degree of obesity and site-specific adipose tissue fatty acid composition in a Mediterranean population. Nutrition. 2011;27(2):170–176.
5.    Paniagua JA, Gallego de la Sacristana A, Romero I, et al. Monounsaturated fat-rich diet prevents central body fat distribution and decreases postprandial adiponectin expression induced by a carbohydrate-rich diet in insulin-resistant subjects. Diabetes Care. 2007;30(7):1717–1723. Epub 2007 Mar 23.
6.    Wadden TA, Webb VL, Moran CH, Bailer BA. Lifestyle modification for obesity: new developments in diet, physical activity, and behavior therapy. Circulation. 2012;125(9):1157–1170.

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