Wednesday, June 30, 2010

Low carb diets and strength training

Just saw this abstract - lower calories whether low carb or not - can help to lose body-weight but won't affect strength? So you don't need carbs to display strength.

Effects of short-term very low-carbohydrate or conventional diet on strength performance

AIM: Weight reduction strategies usually include diet and regular physical activity. A very low-carbohydrate and high protein diet (VLCD) may be preferred instead of a low energy conventional diet (CONV). The effects of VLCD on strength performance are yet to be understood. Aim of the study is to determine the effects of two different restrictive diets on strength performance.
METHODS: Sedentary women were assigned to either a VLCD (less than 40 g carbohydrate; n=12) or a CONV diet (500 to 800 kcal restrictive; 48%, 22% and 30% from carbohydrate, protein and fat, respectively; n=12). Knee extension isokinetic strength tests (3 yen 15 reps at 60 degrees .s-1, with 90 or 180 s rest interval between sets) were performed prior and after a one week diet period.
RESULTS:Both groups reduced body mass (VLCD: -2.6+/-1.0% vs. CONV: -1.9+/-1.3%; P<0.05), with no between diets effect. The sum of the total work in three sets (ATW) was 4850+/-1002 J vs. 4801+/-973 J with 90 s rest interval, and 4812+/-1174 J vs. 4812+/-1210 J with 180 s rest interval, respectively, in the pre vs. post-VLCD period. For CONV, values were 4709+/-729 J vs. 4530+/-996 J with 90 s rest interval, and 4760+/-732 J vs. 4816+/-702 J with 180 s rest interval, respectively, in the pre vs. post-CONV treatment. No significant differences were detected in the ATW between groups.
CONCLUSION: Short-term hypoenergetic diets, irrespective of the carbohydrate content, seem to reduce significantly body mass, but do not impair acute strength performance.


Martin said...

Interesting. The conclusion speaks to "hypoenergetic diets", yet the abstract says nothing about the VLCD being calorie-restricted. It also talks about a reduction of body mass, but doesn't say whether it is fat or lean mass that was lost (although, even with only 1 week, the loss was greater in the VLCD than the CONV diet).

And 1 week? How can you determine any meaningful results in such a short time?

Just another vain attempt to "prove" that a conventional starvation diet is superior to a VLC diet. Ok, if they say so...

John said...

To add to Martin, also the test was knee extension strength of sedentary women. I'd prefer 3-4 weeks with [something like] a squat and chin test of people who strength train regularly.

Chris said...

I agree with you both.

As ever I'm just posting stuff I find of interest.

JP said...

thanks for the study.

I knew from my own experience that you don't really need carbs to perform in the weight room. I have actually become stronger while eating less carbs.