Alternative Day Diet and Protein Consumption.
mermer45
Posts: 77 Member
ADF, IGF-1 and Protein
From the various research (shown below in Notes) it appears that ADF (Alternative Day Fasting) and CR (Calorie Restriction) has many health benefits but to get the most benefit, it may be necessary to restrict protein consumption to no more than 0.8 grams per 1 KG of body weight.
0.8 grams per 1KG is actually the recommended daily amount. However, many people, particularly those on low carb, high protein diets are eating significantly more than this (1.5-1.7 gm per 1KG) in the belief that it is safe.
To put this into context. I weigh 81 KG. Therefore, under this restriction my consumption of protein would be 81 *0.8 = 64.8 grams per day. Each gram of protein has 4 calories. Therefore, I should consume no more than 259 calories per day from protein. If my daily intake is 2000 calories it would suggest that protein should represent roughly 13% of my daily energy requirement.
The aim of reducing protein intake is to reduce IGF-1 levels (see notes below) which is strongly linked to certain cancers and aging. However, it may be worth having a blood test to determine your existing levels of IGF-1. If you have a high IGF-1 blood serum level than you might want to consider the information below. If you have low IGF-1 blood levels then could be already following a low protein diet or you are an exception to the science - in which case please share your results!
NOTES
IGF-1 (Insulin Growth Factor) is a hormone which is very similar to insulin.
Studies have shown that increased levels of IGF lead to increased growth of existing cancer cells.
In addition it is now widely accepted that signalling through the insulin/IGF-1-like receptor pathway is a significant contributor to the biological ageing process in many organisms.
Studies of humans with IGF-1 deficiency have shown exceptionally low levels of cancer and diabetes.(http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3357623/)
Long term CR (Calorie Restriction) is shown to decrease IGF-1 concentration by approximately 40% in rodents, and this reduction in IGF-1 levels is believed to be a major reason why these animal live significantly longer than the control that are not on CR.
However, long term CR does NOT seem to impact levels of IGF-1 in humans IGF-1 levels in healthy humans IF protein intake is high.(http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2673798/). This research suggests that protein intake is more powerful than calorie intake in modulating circulating IGF-1 concentration in humans. The research also shows that when humans who practice CR drop their protein intake to around 80 grams per 100 Kilogram of body weight their IGF-1 levels reduce significantly.
There is evidence that fasting acutely lowers IGF-1 in humans. However, the results of Alternative Diet Fasting and its impact on IGF-1 in humans seems to be mixed. Some studies show a decrease and others an increase in IGF-1 levels. Therefore, one can assume when it comes to ADF other variables such as protein intake are more important in IGF-1 levels.
This information may partly explain why a recent long term study of Rhesus Monkeys did not improve the longevity of a group of monkeys on CR versus a control group of monkeys on a healthy non-restricted diet(http://www.nature.com/nature/journal/vaop/ncurrent/full/nature11432.html). There is speculation that this may be because the monkeys were on a relatively high-protein diet and therefore did not have low levels of IGF-1.
What does seem clear is that CR on humans and mice have shown other health benefits such as significant improvement in insulin sensitivity, and in significant reductions in serum leptin (a circulating hormone that reflects the amount of energy stored in fat tissue), C-reactive protein (a marker of systemic inflammation), insulin and triiodothyronine levels ( it is also worth pointing out that some of the health benefits depend partly on gender).
Summary The evidence, to date, seems to suggest that ADF or other forms of CR in humans are best carried out without high levels of protein intake
From the various research (shown below in Notes) it appears that ADF (Alternative Day Fasting) and CR (Calorie Restriction) has many health benefits but to get the most benefit, it may be necessary to restrict protein consumption to no more than 0.8 grams per 1 KG of body weight.
0.8 grams per 1KG is actually the recommended daily amount. However, many people, particularly those on low carb, high protein diets are eating significantly more than this (1.5-1.7 gm per 1KG) in the belief that it is safe.
To put this into context. I weigh 81 KG. Therefore, under this restriction my consumption of protein would be 81 *0.8 = 64.8 grams per day. Each gram of protein has 4 calories. Therefore, I should consume no more than 259 calories per day from protein. If my daily intake is 2000 calories it would suggest that protein should represent roughly 13% of my daily energy requirement.
The aim of reducing protein intake is to reduce IGF-1 levels (see notes below) which is strongly linked to certain cancers and aging. However, it may be worth having a blood test to determine your existing levels of IGF-1. If you have a high IGF-1 blood serum level than you might want to consider the information below. If you have low IGF-1 blood levels then could be already following a low protein diet or you are an exception to the science - in which case please share your results!
NOTES
IGF-1 (Insulin Growth Factor) is a hormone which is very similar to insulin.
Studies have shown that increased levels of IGF lead to increased growth of existing cancer cells.
In addition it is now widely accepted that signalling through the insulin/IGF-1-like receptor pathway is a significant contributor to the biological ageing process in many organisms.
Studies of humans with IGF-1 deficiency have shown exceptionally low levels of cancer and diabetes.(http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3357623/)
Long term CR (Calorie Restriction) is shown to decrease IGF-1 concentration by approximately 40% in rodents, and this reduction in IGF-1 levels is believed to be a major reason why these animal live significantly longer than the control that are not on CR.
However, long term CR does NOT seem to impact levels of IGF-1 in humans IGF-1 levels in healthy humans IF protein intake is high.(http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2673798/). This research suggests that protein intake is more powerful than calorie intake in modulating circulating IGF-1 concentration in humans. The research also shows that when humans who practice CR drop their protein intake to around 80 grams per 100 Kilogram of body weight their IGF-1 levels reduce significantly.
There is evidence that fasting acutely lowers IGF-1 in humans. However, the results of Alternative Diet Fasting and its impact on IGF-1 in humans seems to be mixed. Some studies show a decrease and others an increase in IGF-1 levels. Therefore, one can assume when it comes to ADF other variables such as protein intake are more important in IGF-1 levels.
This information may partly explain why a recent long term study of Rhesus Monkeys did not improve the longevity of a group of monkeys on CR versus a control group of monkeys on a healthy non-restricted diet(http://www.nature.com/nature/journal/vaop/ncurrent/full/nature11432.html). There is speculation that this may be because the monkeys were on a relatively high-protein diet and therefore did not have low levels of IGF-1.
What does seem clear is that CR on humans and mice have shown other health benefits such as significant improvement in insulin sensitivity, and in significant reductions in serum leptin (a circulating hormone that reflects the amount of energy stored in fat tissue), C-reactive protein (a marker of systemic inflammation), insulin and triiodothyronine levels ( it is also worth pointing out that some of the health benefits depend partly on gender).
Summary The evidence, to date, seems to suggest that ADF or other forms of CR in humans are best carried out without high levels of protein intake
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Replies
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Sounds worth investigating. Do you have some referrences to site?0
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Sounds worth investigating. Do you have some referrences to site?
Yes, they are listed in the notes above....for some reason they didn't post as hyperlinks.0 -
Hey, just wanted to chime in here. We are having a similar discussion over in the intermittent fasting group.
Since seeing the recent BBC documentary on fasting, I have done some research into protein and IGF-1 and found the evidence for a moderate protein diet pretty compelling. I have lowered my intake to 1g/kg/day. I also looked into potential adverse effects of inadequate intake and found research suggesting that 0.8g/kg/day may be marginally inadequate.
One of the concerns is bone density loss. According to some studies, protein intake below 0.9g/kg/day is associated with metabolic changes such as increased parathyroid hormone production, suggesting that your body is trying to make up for what it perceives as decreased calcium availability. Parathyroid hormone is what mobilizes calcium from bones when the body stores of calcium are low. I have found a couple of studies that supported that this happened even in the short term and even at the US RDA recommended levels of 0.8g/kg/day, and one that refutes it (I haven't done a ton of research on this, just a quick search, so there's probably more out there).
http://www.ncbi.nlm.nih.gov/pubmed/12612169
http://www.ajcn.org/content/72/1/168.full
http://www.ncbi.nlm.nih.gov/pubmed/15284373
Protein intake at or below 0.8g/kg/day has also been associated with sarcopenia or muscle loss in older people:
http://www.jacn.org/content/26/6/696S.full
http://www.ajcn.org/content/87/5/1562S.full
Just wanted to put that out there -- I think the link between decreased IGF-1 and lower protein (and specifically methionine) is very interesting but there may be a fine line between the levels shown to decrease IGF-1 and those with adverse effects. One of the studies you referenced showed benefit in decreasing to 0.95g/kg and this seems to be a safe level.0 -
Yes, completely agree. I had come to the same conclusion and decided to keep at around 1gram per kilo, particularly as I'm quite active. So far I've lost around 3.9 kilos in 5 weeks and 3.7 kilos has been body fat, so hopefully it's not too far off.
One thing I would like to understand is if there's any difference between the source of protein ....animal or plant.0 -
So for a 67kg woman, about 65 g protein a day? I'm still a little confused.. but 65 is about right anyways for me..0
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So for a 67kg woman, about 65 g protein a day? I'm still a little confused.. but 65 is about right anyways for me..
Yes, somewhere around 65 grams of protein would be right. If that's about right for you anyway then great!
I gram of protein has 4 calories. So that would mean that you get around 260 calories per day from protein.
If your total calories intake in a day is 1800 calories then protein would represent around 260/1800 * 100 = 14.4%
Lots of people on MFP and particularly those on low carb, high protein diets are averaging more than 30%0 -
Yes, completely agree. I had come to the same conclusion and decided to keep at around 1gram per kilo, particularly as I'm quite active. So far I've lost around 3.9 kilos in 5 weeks and 3.7 kilos has been body fat, so hopefully it's not too far off.
One thing I would like to understand is if there's any difference between the source of protein ....animal or plant.
It seems like there is evidence for the amino acid methionine being of particular concern. A couple of scientific and not-so-scientific references:
http://www.examiner.com/article/advances-aging-research-why-methionine-restriction-is-an-attractive-life-extension-strategy
http://prescribingyoga.blogspot.com/2010/02/low-methionine-theory.html
http://www.oasisofhope.com/media/pdf/met_vegan.pdf
http://www.ncbi.nlm.nih.gov/pubmed/16800846
http://www.ncbi.nlm.nih.gov/pubmed/15924568
Methionine is higher in animal than in plant protein. It seems like most of the studies looking at protein restriction and IGF-1 used vegans as their low protein group. It would be interesting to see a study in humans looking at low protein meat eaters -- I haven't run across one, have you? It does seem that in rodent studies methionine has been singled out as a speficic amino acid "responsible" or largely responsible for the lowering of IGF-1.0 -
Just wanted to add one more good study on methionine in rats:
http://www.ncbi.nlm.nih.gov/pubmed/190396760 -
JSL_MFP, many thanks. I will have a read.
Over the weekend, I've also read the 'China Study' - which seems to be a very reputable publication and very well peer reviewed.
The book makes the case that animal protein encourages cancer cell proliferations, whereas plant proteins do not.
This book first comes to this conclusion by comparing lab results of trying to induce cancer into the different organs of two different species (rats and mice) by using several different types of carcinogens - and then comparing results of those fed on high versus low protein diets. Then testing whether different types of proteins made a difference. In short - animal protein diets of circa 20% were very bad, 5% much less so. Plant based protein had little impact.
The book then looks at China comparing statistical health information with diets. Here it shows that there is a huge difference in cancer rates per 100,000 of the population, depending on the area of China. Those areas in China with high cancer rates are eating 'affluent' more western diets higher in animal protein. Those area that have low cancer rates have a vegetarian style diet. It's not just cancer - heart disease and diabetes, are all correlated to high fat, high protein, animal based, affluent diets.
Ultimately, the book makes the case for a vegan style diet - cutting out all animal protein, including eggs, milk and other diary products.0
