Sport High protein/low carb = Lowered testosterone Is this true?

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I've read off some websites that high protein and low carb diet's eventually "cramp" testosterone:

Research suggests that eating a high-protein, low-carbohydrate diet can cramp your testosterone levels. High amounts of dietary protein in your blood can eventually lower the amount of testosterone produced in your testes, says Incledon, who observed this relationship in a Penn State study of 12 healthy, athletic men.

Your protein intake should be about 16 percent of your daily calories, Incledon says. So, if you're the average 170-pound man who eats 2,900 calories a day, you should eat about 140 grams of protein daily, which is about the amount in two chicken breasts and a 6-ounce can of tuna.

Is there any truth to this? I don't think its true since the dude is saying 16% of intake should be protein, which is BS. But i've read this on more than one site.
 
I've read the same things before, it appears carbs do the same.. But in my own experiences protein is the most anabolic nutrient I know of.

ie.
"Volek, Jeff S., William J. Kraemer, Jill A. Bush, Thomas Incledon, and Mark Boetes. Testosterone and cortisol in relationship to dietary nutrients and resistance exercise. J. Appl. Physiol. 82(1): 49-54, 1997.Manipulation of resistance exercise variables (i.e., intensity, volume, and rest periods) affects the endocrine response to exercise; however, the influence of dietary nutrients on basal and exercise-induced concentrations of hormones is less understood. The present study examined the relationship between dietary nutrients and resting and exercise-induced blood concentrations of testosterone (T) and cortisol (C). Twelve men performed a bench press exercise protocol (5 sets to failure using a 10-repetitions maximum load) and a jump squat protocol (5 sets of 10 repetitions using 30% of each subject's 1-repetition maximum squat) with 2 min of rest between all sets. A blood sample was obtained at preexercise and 5 min postexercise for determination of serum T and C. Subjects also completed detailed dietary food records for a total of 17 days. There was a significant (P 0.05) increase in postexercise T compared with preexercise values for both the bench press (7.4%) and jump squat (15.1%) protocols; however, C was not significantly different from preexercise concentrations. Significant correlations were observed between preexercise T and percent energy protein (r = 0.71), percent energy fat (r = 0.72), saturated fatty acids (g · 1,000 kcal1 · day1; r = 0.77), monounsaturated fatty acids (g · 1,000 kcal1 · day1; r = 0.79), the polyunsaturated fat-to-saturated fat ratio (r = 0.63), and the protein-to-carbohydrate ratio (r = 0.59). There were no significant correlations observed between any nutritional variables and preexercise C or the absolute increase in T and C after exercise. These data confirm that high-intensity resistance exercise results in elevated postexercise T concentrations. A more impressive finding was that dietary nutrients may be capable of modulating resting concentrations of T. "
 
I've read the same things before, it appears carbs do the same.. But in my own experiences protein is the most anabolic nutrient I know of.

ie.
"Volek, Jeff S., William J. Kraemer, Jill A. Bush, Thomas Incledon, and Mark Boetes. Testosterone and cortisol in relationship to dietary nutrients and resistance exercise. J. Appl. Physiol. 82(1): 49-54, 1997.Manipulation of resistance exercise variables (i.e., intensity, volume, and rest periods) affects the endocrine response to exercise; however, the influence of dietary nutrients on basal and exercise-induced concentrations of hormones is less understood. The present study examined the relationship between dietary nutrients and resting and exercise-induced blood concentrations of testosterone (T) and cortisol (C). Twelve men performed a bench press exercise protocol (5 sets to failure using a 10-repetitions maximum load) and a jump squat protocol (5 sets of 10 repetitions using 30% of each subje

ct's 1-repetition maximum squat) with 2 min of rest between all sets. A blood sample was obtained at preexercise and 5 min postexercise for determination of serum T and C. Subjects also completed detailed dietary food records for a total of 17 days. There was a significant (P 0.05) increase in postexercise T compared with preexercise values for both the bench press (7.4%) and jump squat (15.1%) protocols; however, C was not significantly different from preexercise concentrations. Significant correlations were observed between preexercise T and percent energy protein (r = 0.71), percent energy fat (r = 0.72), saturated fatty acids (g · 1,000 kcal1 · day1; r = 0.77), monounsaturated fatty acids (g · 1,000 kcal1 · day1; r = 0.79), the polyunsaturated fat-to-saturated fat ratio (r = 0.63), and the protein-to-carbohydrate ratio (r = 0.59). There were no significant correlations observed between any nutritional variables and preexercise C or the absolute increase in T and C after exercise. These data confirm that high-intensity resistance exercise results in elevated postexercise T concentrations. A more impressive finding was that dietary nutrients may be capable of modulating resting concentrations of T. "

Exactly. I always thoughts high protein + fat increases testosterone, i know that carbs can be important for maintaining and building muscle. But I don't think testosterone gets lowered unless carbs are very very low (50 and sub ? ). I'm keeping my current carb intake from 70-100g. WW bread at breakfast, and fruits at night.

Gonna ask T-nation....
 
I haven't been able to find any literature to the contrary. It doesn't look like T levels are impacted by a low carb, high protein diet.

Though I'd be more concerned about the impact to the liver and kidneys in any high protein diet.

On a more serious note, I wish this forum had a sticky thread dedicated to steps required for looking like mreik's avatar.
 
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I've read off some websites that high protein and low carb diet's eventually "cramp" testosterone:
There could be some truth to low carbs affecting test levels, I'm only taking a stab in the dark at the moment but I would have thought that changing your body's source of energy would have a knock-on effect on your endocrine system as it might affect your bodies chemical balance

I'm reading more of my Endocrinology text book at lunch so I'll look for a piece on carb intake :)
 
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