T Nation

Higher Protein, Lower Carb and Weight Loss


Here's an interesting meta-analysis demonstrating that during weight loss, different dietary intakes can impact the proportion of fat mass, lean mass, etc lost.


Effects of variation in protein and carbohydrate intake on body mass and composition during energy restriction: a meta-regression 1 ,2 ,3

James W Krieger1, Harry S Sitren1, Michael J Daniels1 and Bobbi Langkamp-Henken1

1 From the Departments of Food Science and Human Nutrition (JWK, HSS, and BL-H) and of Statistics (MJD), University of Florida, Gainesville, FL.

Background: It is unclear whether low-carbohydrate, high-protein, weight-loss diets benefit body mass and composition beyond energy restriction alone.

Objective: The objective was to use meta-regression to determine the effects of variations in protein and carbohydrate intakes on body mass and composition during energy restriction.

Design: English-language studies with a dietary intervention of 4200 kJ/d (1000 kcal/d), with a duration of 4 wk, and conducted in subjects aged 19 y were considered eligible for inclusion. A self-reported intake in conjunction with a biological marker of macronutrient intake was required as a minimum level of dietary control. A total of 87 studies comprising 165 intervention groups met the inclusion criteria.

Results: After control for energy intake, diets consisting of less than or equal to 35?41.4% energy from carbohydrate were associated with a 1.74 kg greater loss of body mass, a 0.69 kg greater loss of fat-free mass, a 1.29% greater loss in percentage body fat, and a 2.05 kg greater loss of fat mass than were diets with a higher percentage of energy from carbohydrate. In studies that were conducted for >12 wk, these differences increased to 6.56 kg, 1.74 kg, 3.55%, and 5.57 kg, respectively. Protein intakes of >1.05 g/kg were associated with 0.60 kg additional fat-free mass retention compared with diets with protein intakes 1.05 g/kg. In studies conducted for >12 wk, this difference increased to 1.21 kg. No significant effects of protein intake on loss of either body mass or fat mass were observed.

Conclusion: Low-carbohydrate, high-protein diets favorably affect body mass and composition independent of energy intake, which in part supports the proposed metabolic advantage of these diets.

My comments:

For the record, Meta-Analysis isn't definative as all of the studies included had methodological differences and likely many design flaws. But Meta-Analysis does give us a general survey of the literature in a specific area and a review of what direction the literature points.

This review does point to the fact that perhaps calorie intake isn't the only important thing in governing the type of weight gained or lost with energy restriction.


Wow..pretty much supports what most of us do here to cut eh?


From looking at most of these types of studies where they compare macronutrient makeup, the ones that seem to favor one over the other have self reporting which is generally unreliable, while the studies that show no difference are usually controlled better.


Thanks for posting that JB. When I focus on fat loss, I usually aim for a simple low-carb approach with a slight increase in healthy fats while bumping up my protein to 1.25 g/lb body mass. I try not to cut carbs for long cycles as the workouts are exhaustive and fatiguing despite my use of Surge & stimulants.

On a side note, I checked a couple of pages here on r-ala but there's no CONCLUSIVE information as to how much to consume, when exactly to use it, or if any new studies exist clarifying whether or not this is a worthwhile supplement. I also discovered there's a new more bioavailable form called k r-ala. Unfortunately, it seems to be patented and is very expensive relative to other compounds that promise similar effects. Any comments on the issue?

In 2004, one of the T-Nation mods touted r-ala as a "must-have" but in 2005 Barr discouraged the hype (citing that it might even promote fat accumulation) despite that some coaches raved about it. As someone who researches homoepathic remedies, I've come across articles by Dr. Mercola who advises healthy individuals to consume up to 600 mg a day of ala for its antioxidant effects - but I have an arsenal of antioxidant protection so I'm not wasting my $ on k r-ala for that benefit...

Any input would be greatly appreciated. And last question, would you stack k r-ala with ALCAR according to the claims of the latest research?

We need an article on the matter. Again thanks and peace be with you!


Could you transfer this info to say that on a bulking diet a higher protein, lower carb approach (a la Anabolic diet) could lead to more muscle and less fat gains?


Thanks JB! exactly, by ultilizing your protocals, I've gained 5.3 lbs of LBM while only 0.6 lbs of fat mass. This case study is exactly what I need!

Only problem is my professor told me self-reported caloric intakes are usualy rubbish. Are there any properly controlled studies to prove what I believe is right from my experience? Not some rubbish study like the one you linked?

"A self-reported intake in conjunction with a biological marker of macronutrient intake was required as a minimum level of dietary control."