Rogue Health and Fitness

Low-carb diet does not compromise strength and power

In my humble opinion, this study needs to be read and understood by all those people who claim that dietary carbohydrates are necessary for athletics of any kind: Effects of a short-term carbohydrate-restricted diet on strength and power performance

The purpose of the study was to examine the effects of switching from a habitual diet to a carbohydrate-restricted diet (CRD) on strength and power performance in trained men (n = 16) and women (n = 15). Subjects performed handgrip dynamometry, vertical jump, 1RM bench press and back squat, maximum-repetition bench press, and a 30-second Wingate anaerobic cycling test after consuming a habitual diet (40.7% carbohydrate, 22.2% protein, and 34.4% fat) for 7 days and again after following a CRD (5.4% carbohydrate, 35.1% protein, and 53.6% fat) for 7 days. Before both testing sessions, body weight and composition were examined using bioelectrical impedance analysis. Three 2 × 2 multiple analyses of variance were used to compare performance variables between the habitual diet and CRD. Subjects consumed significantly fewer (p < 0.05) total kilocalories during the CRD (2,156.55 ± 126.7) compared with the habitual diet (2,537.43 ± 99.5). Body mass decreased significantly (p < 0.05). Despite a reduction in body mass, strength and power outputs were maintained for men and women during the CRD. These findings may have implications for sports that use weight classes, and in which strength and power are determinants of success. A CRD may be an alternative method for short-term weight loss without compromising strength and power outputs. The use of a 7-day CRD could replace weight loss methods employing severe dehydration before competition.

Note that calorie consumption spontaneously declined, which is what usually or always happens when carbs are restricted. Weight loss occurred, yet power and strength did not decline, which would indicate that the weight loss was almost entirely fat tissue.

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9 comments
Steve Parker, M.D. says May 29, 2014

Good to know. I’m glad to see they didn’t test CRD strength during the first 3 or 4 days after the switch. I’ve read elsewhere that it takes 3-4 weeks to adapt to very-low-carb eating. Apparently not, in terms of strength and power. Wonder about aerobic fitness/endurance.

-Steve

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Mangan says May 29, 2014

One reads lots of bodybuilders saying how carbs are so necessary, but I think that’s just old school thinking, the same as the sat fat is bad for you stuff. Nice to see this in an actual study. Also, a number of studies show that carbs don’t cause an increase in muscle anabolism when enough protein is present. So, carbs don;t seem to be very necessary.

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eah says May 30, 2014

BBC: Light bedrooms ‘link to obesity’

All fat people need to do is turn off all the lights at night and close the curtains and they’ll lose weight.

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ironthumb michaelangelo says June 7, 2014

I love this one man keep it up

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Mangan says June 7, 2014

Ironthumb, always good to see you around here. And each, thanks for the link.

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Lauren says February 2, 2015

“Weight loss occurred, yet power and strength did not decline, which would indicate that the weight loss was almost entirely fat tissue.”

I’m not clear why this is so. Can you clarify?

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    P. D. Mangan says February 2, 2015

    Lauren, power and strength come from muscle tissue. If a substantial portion of the weight loss had been muscle, then power and strength would have declined. Since it didn’t, we can conclude that most or all of the weight loss was not muscle, but fat.

    Reply
Lauren says February 2, 2015

I don’t have access to the full article, so perhaps the authors already explained this, but how do we know it wasn’t loss of water weight? I was under the impression that low carb diets (and the low carb diet is this study is very low based on the numbers in the abstract) are known for decreasing water weight, especially in the short-term. That said, I think you are probably more right than wrong about the subjects’ weight loss being due to loss of fat as the CRD diet in the study had significantly less calories.

Reply
    P. D. Mangan says February 2, 2015

    Lauren, you’re correct, some of the weight loss would have been water. However, calorie consumption dropped considerably by about 400 calories a day, so that would have caused fat loss. I think we can also conclude, based on strength and power, that little to no muscle mass was lost.

    Reply
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