Intermittent Fasting Study - Results: Decreased Testosterone And T3

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https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-016-1044-0


"Abstract

Background


Intermittent fasting (IF) is an increasingly popular dietary approach used for weight loss and overall health. While there is an increasing body of evidence demonstrating beneficial effects of IF on blood lipids and other health outcomes in the overweight and obese, limited data are available about the effect of IF in athletes. Thus, the present study sought to investigate the effects of a modified IF protocol (i.e. time-restricted feeding) during resistance training in healthy resistance-trained males.


Methods

Thirty-four resistance-trained males were randomly assigned to time-restricted feeding (TRF) or normal diet group (ND). TRF subjects consumed 100 % of their energy needs in an 8-h period of time each day, with their caloric intake divided into three meals consumed at 1 p.m., 4 p.m., and 8 p.m. The remaining 16 h per 24-h period made up the fasting period. Subjects in the ND group consumed 100 % of their energy needs divided into three meals consumed at 8 a.m., 1 p.m., and 8 p.m. Groups were matched for kilocalories consumed and macronutrient distribution (TRF 2826 ± 412.3 kcal/day, carbohydrates 53.2 ± 1.4 %, fat 24.7 ± 3.1 %, protein 22.1 ± 2.6 %, ND 3007 ± 444.7 kcal/day, carbohydrates 54.7 ± 2.2 %, fat 23.9 ± 3.5 %, protein 21.4 ± 1.8). Subjects were tested before and after 8 weeks of the assigned diet and standardized resistance training program. Fat mass and fat-free mass were assessed by dual-energy x-ray absorptiometry and muscle area of the thigh and arm were measured using an anthropometric system. Total and free testosterone, insulin-like growth factor 1, blood glucose, insulin, adiponectin, leptin, triiodothyronine, thyroid stimulating hormone, interleukin-6, interleukin-1β, tumor necrosis factor α, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides were measured. Bench press and leg press maximal strength, resting energy expenditure, and respiratory ratio were also tested.


Results

After 8 weeks, the 2 Way ANOVA (Time * Diet interaction) showed a decrease in fat mass in TRF compared to ND (p = 0.0448), while fat-free mass, muscle area of the arm and thigh, and maximal strength were maintained in both groups. Testosterone and insulin-like growth factor 1 decreased significantly in TRF, with no changes in ND (p = 0.0476; p = 0.0397). Adiponectin increased (p = 0.0000) in TRF while total leptin decreased (p = 0.0001), although not when adjusted for fat mass. Triiodothyronine decreased in TRF, but no significant changes were detected in thyroid-stimulating hormone, total cholesterol, high-density lipoprotein, low-density lipoprotein, or triglycerides. Resting energy expenditure was unchanged, but a significant decrease in respiratory ratio was observed in the TRF group.


Conclusions

Our results suggest that an intermittent fasting program in which all calories are consumed in an 8-h window each day, in conjunction with resistance training, could improve some health-related biomarkers, decrease fat mass, and maintain muscle mass in resistance-trained males."

Looks like they drew the wrong conclusions from the study - looking purely at fat and muscle mass opposed to the hormonal deregulation in Testosterone and Thyroid.



 
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great find, thank you!

The "8 hour feeding window" fasting preserves lean mass BUT lowers T3 and lowers testosterone...
 

Agent207

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I've never been sold on IF, but I feel fasting to be good once a week or so though.
 
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superhuman

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Once again look at the whole. The reason T3 and Test levels drop is because they was basiclly in a calorie deficit so they lost body fat, so that is something that happens to most people when they loose fat
 
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Once again look at the whole. The reason T3 and Test levels drop is because they was basiclly in a calorie deficit so they lost body fat, so that is something that happens to most people when they loose fat

I don't agree. The people who were just lowering fat didn't lose T or T3. It was the 8 hour feeding window that caused it. Not the fat loss
 

jaywills

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"Groups were matched for kilocalories consumed and macronutrient distribution "

The study looked at IF vs non-IF; nutrition was matched.

Agreed with @ecstatichamster
 

PUTFOT

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What if it lowers plasma levels because of t and t3 going into tissue?
 

Regina

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Effects of eight weeks of time-restricted feeding (16/8) on basal metabolism, maximal strength, body composition, inflammation, and cardiovascular risk factors in resistance-trained males | Journal of Translational Medicine | Full Text


"Abstract

Background


Intermittent fasting (IF) is an increasingly popular dietary approach used for weight loss and overall health. While there is an increasing body of evidence demonstrating beneficial effects of IF on blood lipids and other health outcomes in the overweight and obese, limited data are available about the effect of IF in athletes. Thus, the present study sought to investigate the effects of a modified IF protocol (i.e. time-restricted feeding) during resistance training in healthy resistance-trained males.


Methods

Thirty-four resistance-trained males were randomly assigned to time-restricted feeding (TRF) or normal diet group (ND). TRF subjects consumed 100 % of their energy needs in an 8-h period of time each day, with their caloric intake divided into three meals consumed at 1 p.m., 4 p.m., and 8 p.m. The remaining 16 h per 24-h period made up the fasting period. Subjects in the ND group consumed 100 % of their energy needs divided into three meals consumed at 8 a.m., 1 p.m., and 8 p.m. Groups were matched for kilocalories consumed and macronutrient distribution (TRF 2826 ± 412.3 kcal/day, carbohydrates 53.2 ± 1.4 %, fat 24.7 ± 3.1 %, protein 22.1 ± 2.6 %, ND 3007 ± 444.7 kcal/day, carbohydrates 54.7 ± 2.2 %, fat 23.9 ± 3.5 %, protein 21.4 ± 1.8). Subjects were tested before and after 8 weeks of the assigned diet and standardized resistance training program. Fat mass and fat-free mass were assessed by dual-energy x-ray absorptiometry and muscle area of the thigh and arm were measured using an anthropometric system. Total and free testosterone, insulin-like growth factor 1, blood glucose, insulin, adiponectin, leptin, triiodothyronine, thyroid stimulating hormone, interleukin-6, interleukin-1β, tumor necrosis factor α, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides were measured. Bench press and leg press maximal strength, resting energy expenditure, and respiratory ratio were also tested.


Results

After 8 weeks, the 2 Way ANOVA (Time * Diet interaction) showed a decrease in fat mass in TRF compared to ND (p = 0.0448), while fat-free mass, muscle area of the arm and thigh, and maximal strength were maintained in both groups. Testosterone and insulin-like growth factor 1 decreased significantly in TRF, with no changes in ND (p = 0.0476; p = 0.0397). Adiponectin increased (p = 0.0000) in TRF while total leptin decreased (p = 0.0001), although not when adjusted for fat mass. Triiodothyronine decreased in TRF, but no significant changes were detected in thyroid-stimulating hormone, total cholesterol, high-density lipoprotein, low-density lipoprotein, or triglycerides. Resting energy expenditure was unchanged, but a significant decrease in respiratory ratio was observed in the TRF group.


Conclusions

Our results suggest that an intermittent fasting program in which all calories are consumed in an 8-h window each day, in conjunction with resistance training, could improve some health-related biomarkers, decrease fat mass, and maintain muscle mass in resistance-trained males."

Looks like they drew the wrong conclusions from the study - looking purely at fat and muscle mass opposed to the hormonal deregulation in Testosterone and Thyroid.


Yep. I wish I had before and after photos of me.
 

Gl;itch.e

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I'd like to know WHEN they are doing the blood draws. Surely if they are taking them during or towards the end of the fasting period when cortisol/adrenaline is high its going to show unfavourable changes in Test and T3. But if measured after feeding might show a different story.
 

Queequeg

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Doesn't IF put the body in a state of lower metabolism for survival purposes. It makes sense that hormones that increase metabolism would then drop. I think Ray's argument against IF is that it is too stressful and catabolic. What is interesting is that the change in Cortisol is not statistically different.
 

WestCoaster

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So basically it's a study of skipping breakfast or not. It's interesting, but there are always other factors at play.
- Testosterone can significantly rise and fall throughout the day directly in response to Cortisol (they oppose each other)
- Testosterone significantly rises and falls given how much sleep someone gets hour to hour (more sleep = more Test)
- Testosterone levels are generally higher in the middle of the night when you are sleeping which means it's probably best to test it first thing in the morning
- Fasting is also increases cortisol (but that is it's advantage to weight loss provided someone's levels aren't out of whack). So did they test them during the fasting phase or after their eating? It would have risen during their feeding window
- Was the TRD group fasting when they were actually hungry? Avoiding food when your body is telling you to eat can cause a cortisol surge. This is a major problem with people who try IF, which leads me to the next point
- Fasting can cause the metabolism to slow down (which will lower Test, for the duration of the fast).

Assuming all things are created equal (which is impossible), the fasting group will always have a bigger acute cortisol spike during the day when they are fasting which means their T will be lower during that time. So it's important WHEN the blood was drawn. Was it drawn at the end of the fasting period in the TRD group but after the ND group had it's first meal? That would make a massive difference. The meal would have suppressed Cortisol allowing Testosterone to run it's course, whereas the fasting group would have high levels of cortisol suppressing their Test.

As I said, Test is highest at night when you're sleeping and whose to say the TRD group may have higher Test levels during that time than than the ND group.
 

PUTFOT

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Intermittent fasting increases androgen receptor sensitivity significantly. I've seen studies where it significantly increased t levels after re-feeding. More sensitive androgen receptors require less androgens for the same androgenic effects anyway. Studies point to short-fasting increasing DHEA and dopamine, detoxifying of chemicals (xenoestrogens) by autophagy, and increasing brain levels of BDNF, a major anti-depressant.
 

jyb

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You didn't mention in the title that it's combined with resistance training for athletes. I note that the TSH and cortisol are unchanged and TNF is improved under their IF program.

Doesn't IF put the body in a state of lower metabolism for survival purposes. It makes sense that hormones that increase metabolism would then drop. I think Ray's argument against IF is that it is too stressful and catabolic. What is interesting is that the change in Cortisol is not statistically different.

This is only IF with calories maintained, it doesn't look very stressful to me. It is however combined with an athletes program, which makes the conclusions possibly irrelevant for ordinary people. Under normal metabolism I have not seen Ray write that IF is incompatible with good health.
 
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Wagner83

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Ray has said individuals with good liver function can store enough glycogen to go for much more than 8 hours without eating and still not be stressed. So if (iF) IF has a positive effect on the digestive system and the whole body, then maybe it's possible to thrive on IF.
 

encerent

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They recommend it,

Conclusions
Our results suggest that an intermittent fasting program in which all calories are consumed in an 8-h window each day, in conjunction with resistance training, could improve some health-related biomarkers, decrease fat mass, and maintain muscle mass in resistance-trained males.
 

Regina

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[ moderator edit: threads merged ]

16/8 IF Causes Fat Loss But Reduces Test, T3 And RER, Causes Shift To Fatty Acids For Fuel

also increases cortisol

Effects of eight weeks of time-restricted feeding (16/8) on basal metabolism, maximal strength, body composition, inflammation, and cardiovascular risk factors in resistance-trained males
I'm pretty much a textbook case of IF being a disaster for me. Seemed fine when I was relatively sedentary (long walks with the dog everyday).
But when I went back to aikido, I very soon looked like Iggy Pop when he was a heroin addict. Ripped but concentration camp thin and neurotic. I most definitely had the endorphin high and felt "powerful" (delusionally) - even though recoveries were brutal. I think I caused insulin resistance, crazy cortisol and damaged thyroid.
 
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