Low-Carb Diet Beats Low-Fat, Calorie-Restricted Diet

Body mass index 38

Body mass index 38

I found one of the early studies (2003) demonstrating the effectiveness and safety of an Atkins-style diet in the severely obese.  Doctors traditionally have been hesitant to recommend the Atkins diet out of concern for tolerability and potential increased atherosclerosis complication such as heart attacks, strokes, and poor circulation.


The study enrolled 132 subjects with an average body mass index of 43, including 77 blacks and 23 women.  39% had diabetes, 43% had metabolic syndrome.  They were randomly assigned to either . . .

  1. a low-carb diet without caloric restriction (carbohydrates limited to 30 gm/day; vegetables and fruits with high ratios of fiber to carbohydrate were recommended), or
  2. a low-fat, calorie-restricted diet. 

Subjects followed their diets for six months.  The researchers never specified, but I’m assuming the diabetics were all type 2. 


The drop-out rate was equally high in both groups: only 79 subjects completed the study.  The low-carb group lost 5.8 kg (13 lb); the low-fat group lost 1.9 kg (4 lb).  Analysis included the drop-outs, for reasons unclear to me.  White subjects lost more weight than blacks: 13 versus 5 kg (29 versus 11 lb).  Total cholesterol, HDL cholesterol, and LDL cholesterol levels did not change significantly within or between groups.  [HDL usually rises on a low-carb diet.]   Triglycerides fell 20% in the low-carb group and 4% in the other group.  For subjects with diabetes, glucose levels fell 26 mg/dl in the low-carb group compared to 5 mg/dl in the low-fat group.  Uric acid levels didn’t change in either group.  [Elevated uric acid levels can cause gout.]  No significant adverse reactions attibutable to the diets were recorded in either group.  Glycosylated hemoglobin fell from 7.8 to 7.2% in the low-carb group, with no change in the low-fat group.   

Take-Home Points  

It’s a small study, so results may not be very accurate or generalizable to other populations.

In this cohort with a high prevalence of diabetes, the low-carb diet was more effective than the low-fat/calorie-restricted diet for weight loss, with no adverse lipid changes to suggest increased long-term cardiovascular risk.  The low-carb diet helped control diabetes. 

Steve Parker, M.D. 

Reference:  Samaha, Frederick, et al.  A low-carbohydrate as compared with a low-fat diet in severe obesity.  New England Journal of Medicine, 348 (2003): 2,074-2,081.


Filed under Carbohydrate, Overweight and Obesity, Weight Loss

2 responses to “Low-Carb Diet Beats Low-Fat, Calorie-Restricted Diet

  1. Anthony Cerciello

    I am a 70 year young white male with a family history of diabetes. I am a type 2 diabetic. I’m very interested in the CR diet and have been following a high protein, low
    carb diet. I was 235 on June 1, 09 and now on 7/1/9 I’m 229. My goal is 200 lbs or lower. My recent labs were LDL 121, HDL
    41 and Tg 262. I walk two hrs a day, swim 3 times a week, 75 minutes each time for a total of approximately 5 1/2 miles. The problem I have is with carbs,
    I gave up pasta, beans, rice, bread and fruit. Presently my blood sugars average 135. This month I had given up eating cheese which I consumed in pretty big quantities and eggs, averaging 2 dozen a week. I also ate minimal amounts of turkery and chicken. I do eat salads everyday and consume 12oz daily with only a vinegar and oil dressing. My question is will I have to consume copious amounts of vegetables to feel satisfied. I recently started eating salmon with my salads and find that very satisfying. Thank you, Tony Cerciello

    • Hi, Tony. Good to hear from you. Congratulations on your weight-loss success!

      I will assume that “CR” means carbohydrate restricted.

      Regarding your question: Many people eating salads do need to eat quite a bit of it for that sense of fullness that will last. Sounds like you’re one of them. Maybe it’s the protein in the salmon that’s helping with satiety.

      You have an impressive exercise program that should yield many benefits.