Nutrition
Recent Study Shows Low Carb Diets More Effective Than Low Fat Diets Long Term
A recent study in the New England Journal of Medicine showed better fat loss over the long run with low-carb and “Mediterranean” diets than a low-fat diet (Shai I, Schwarzfuchs D, Henkin Y, Shahar DR, Witkow S, Greenberg I, Golan R, Fraser D, Bolotin A, Vardi H, Tangi-Rozental O, Zuk-Ramot R, Sarusi B, Brickner D, Schwartz Z, Sheiner E, Marko R, Katorza E, Thiery J, Fiedler GM, Blüher M, Stumvoll M, Stampfer MJ. Weight loss with a low-carbohydrate, Mediterranean, or low-fat diet. N Engl J Med. 2008 Jul 17;359(3):229-41.)
ABSTRACT
Background Trials comparing the effectiveness and safety of weight-loss diets are frequently limited by short follow-up times and high dropout rates.
Methods In this 2-year trial, we randomly assigned 322 moderately obese subjects (mean age, 52 years; mean body-mass index [the weight in kilograms divided by the square of the height in meters],31; male sex, 86%) to one of three diets: low-fat, restricted-calorie; Mediterranean, restricted-calorie; or low-carbohydrate, non–restricted-calorie.
Results The rate of adherence to a study diet was 95.4% at 1 year and 84.6% at 2 years. The Mediterranean-diet group consumed the largest amounts of dietary fiber and had the highest ratio of monounsaturated to saturated fat (P<0.05 for all comparisons among treatment groups). The low-carbohydrate group consumed the smallest amount of carbohydrates and the largest amounts of fat, protein, and cholesterol and had the highest percentage of participants with detectable urinary ketones (P<0.05 for all comparisons among treatment groups). The mean weight loss was 2.9 kg for the low-fat group, 4.4 kg for the Mediterranean-diet group, and 4.7 kg for the low-carbohydrate group (P<0.001 for the interaction between diet group and time); among the 272 participants who completed the intervention, the mean weight losses were 3.3 kg, 4.6 kg, and 5.5 kg, respectively. The relative reduction in the ratio of total cholesterol to high-density lipoprotein cholesterol was 20% in the low-carbohydrate group and 12% in the low-fat group (P=0.01). Among the 36 subjects with diabetes, changes in fasting plasma glucose and insulin levels were more favorable among those assigned to the Mediterranean diet than among those assigned to the low-fat diet (P<0.001 for the interaction among diabetes and Mediterranean diet and time with respect to fasting glucose levels).
Conclusions Mediterranean and low-carbohydrate diets may be effective alternatives to low-fat diets. The more favorable effects on lipids (with the low-carbohydrate diet) and on glycemic control (with the Mediterranean diet) suggest that personal preferences and metabolic considerations might inform individualized tailoring of dietary interventions.
What’s most interesting about this is, despite the low-carb group not being restricted to a specific daily calorie intake like the Mediterranean and low-fat groups (1,800 calories per day for men, 1,500 for women), but rather limiting carbohydrates to 20 grams per day for the first two months followed by 120 grams per day, and despite being advised to choose vegetarian sources of protein, which are generally lower quality than animal sources, they had the greatest weight loss. Additionally, the low-carb group had the greatest increases in HDL and greatest decreases in triglyceride levels. The low-carb group also had the greatest decrease in the ratio of total cholesterol to HDL, nearly twice that of the low-fat group (20% versus 12%).
I am surprised the weight loss for each of the groups was so low based on the calorie and carbohydrate intake guidelines, and strongly suspect poor compliance, very sedentary subjects, or both. If the subjects were actually following the guidelines I expect the weight loss would have been far greater for all groups.
I am also disappointed the dietitians advised the low-carb group to choose vegetarian sources of protein, as I suspect better weight loss and at least equal improvements in lipid profiles had animal sources been chosen.
In any case, it is further proof of the benefits of a higher-protein, lower-carbohydrate diet and it’s viability as an alternative to high-carb, low-fat diets. I have consistently seen better results in my own training and with my personal training clients with higher-protein and lower-carbohydrate intakes.
N.O. Supplements? No Way!
The following article on nitric oxide supplements is published here with permission from the author, Ellen Coleman, RD, MA, MPH.
Supplements that allegedly increase nitric oxide (NO) levels within the body are being heavily marketed to build muscles. “Nitric oxide” supplements supposedly: 1) promote an extended “muscle pump;” 2) signal muscle growth and speed recovery; and 3) increase muscle strength and improve muscle stamina. Nitric oxide (a gas manufactured by the body) is a key signaling molecule in the cardiovascular system. It is different from other known signal molecules and so unstable that it is converted to nitrate and nitrite within seconds.
Nitric oxide regulates blood pressure and acts as a gatekeeper of blood flow to different organs. In addition to vascular regulation, nitric oxide plays an important role in immune responses and neuronal signal transmission. The 1998 Nobel Prize in Physiology or Medicine was awarded for discoveries concerning nitric oxide as a signal molecule (see Nobel webpage) – a fact which some websites capitalize on to promote their “nitric oxide” supplements. The non-essential amino acid arginine is the substrate for the nitric oxide synthase enzyme, which catalyzes the oxidation of arginine to produce nitric oxide and citrulline. › Continue reading
Calculating the Daily Calorie Deficit For Maximum Fat Loss
In books and articles on fat loss it is common to see arbitrary recommendations for daily calorie intake or deficit, such as 1,200 calories per day for women and 1,500 calories per day for men, or a deficit of 500 to 1000 calories per day to lose 1 to 2 pounds of fat per week. The problem with arbitrary calorie intakes is obvious - not everybody has the same daily calorie expenditure so the resulting deficit will vary significantly between people. Apparently the problem with arbitrary deficits is not so obvious - many personal trainers and health professionals routinely recommend a daily calorie deficit of 500 to 1000 calories for everybody - a range that is too low for some and too high for others. › Continue reading
Estimating Daily Calorie Expenditure
Whether you’re trying to maintain your current bodyweight, gain muscle or lose fat, it is necessary to estimate daily calorie expenditure as a starting point for determining the calorie intake appropriate to your goals. The key words here are estimate and starting point. No formula or method of measurement is perfect. No matter how good something looks on paper, what ultimately matters is practical results. Whatever your initial estimate, you will need to keep records of calorie intake and goal-relevant measurements and adjust your intake accordingly. › Continue reading
Basic Guidelines for Fat Loss
This is meant as a set of basic guidelines for fat loss, and is nowhere near a complete discussion of the topic. More advanced, detailed guidelines will be posted in future articles as well as an upcoming book.
While numerous factors affect fat gain and loss, by far the most important is energy balance - calorie intake versus calorie expenditure. If you consume more calories than your body burns over a period of time, you will gain fat. If you want to lose fat, you must consume fewer calories than your body burns. There are three basic ways to accomplish this: › Continue reading