The FastDay Forum

I can't get access to the second study, so I can't comment on it, but having read far too many such studies, I would have to say,

1. The study was very short. When I have investigated claims for other dietary strategies that were based on studies lasting 3 months or less, I have found that almost always, the effect they noted faded out if the diet was continued.

2. The study was probably conducted in a very small group of people, perhaps young students (a common group found in nutritional studies run at universities) making it not necessarily reproducible in larger populations.

3. There are literally hundreds of factors that have each been associated with cancer. Researchers focusing on one always treat it in isolation ignoring the complexity of the disease, which is of course, not one disease but hundreds of different malfunctions which have in common only that they lead to unfettered cell growth.

4. Most importantly, there are likely dozens of other factors beyond protein intake that affect IGF-1 levels, and the research about the benefits of cutting it seem to ignore the other research that shows that higher IGF-1 levels apparently are protective in the elderly. http://www.eurekalert.org/pub_releases/ ... 052308.php

5. The study that found lowered protein lowered IGF-1 lowered protein intake from what looked to me to be a ridiculously high level. Almost twice that .8 g/KG that my estimates and others' are based on. That level would only make sense for someone eating a very low carb diet. OTOH, did that study look at whether muscle was conserved on that CR diet? IGF-1 dropping while a the person is burning through heart muscle wouldn't excite me. And if the CR they are talking about involved intermittent fasting, that could be an issue.

Unhealthy starvation diets like that HCG fad diet produce weight loss that does lead to muscle wasting. More importantly, muscle wasting will send signals to the brain that will slow the metabolism long term and make regain almost impossible to avoid going forward. Successful maintenance requires that you not frighten your hypothalamus into thinking you are starving, because if it thinks that it will adjust matters so that you top off the fat supply, and then some, as soon as possible!

[carorees]

Sorry, @peebles I don't know why you can't access that link as it works fine for me!

Anyway, to summarise that paper: they took people who had been practising calorie restriction for an average of 6 years and looked at IGF-1 and IGFBP-3. They found that found that there were no differences in serum IGF-1 and IGFBP-3 concentrations, and IGF-1 : IGFBP-3 ratio between the CR and Western diet groups but that fasting insulin, C-reactive protein and triiodothyronine concentration were significantly lower in the CR group than in the Western diet group. The authors suggest that these data provide evidence that, in contrast to the decrease in IGF-1 in rodents, a reduction of IGF-1 expression is not a component of the adaptive response to long-term CR in humans. On the other hand, fasting for 10 days markedly reduces serum IGF-1 concentration into the range observed for growth hormone- deficient patients (Thissen et al., 1994). Moreover, the changes of serum IGF-1 during fasting and refeeding are closely correlated with the rate of excretion of urinary urea, a marker of nitrogen balance and protein intake (Clemmons et al., 1981). Therefore, they conducted additional studies to evaluate the importance of long-term protein intake in modulating serum IGF-1 concentration in humans. In one study, they evaluated serum IGF-1 and IGFBP-3 concentrations, and IGF-1 : IGFBP-3 ratio in 28 vegans who had been consuming a moderately protein-restricted (PR) diet (0.76 g kg–1 per day; ~10% of intake from protein) for ~5 years age-matched with 28 members of the Calorie Restriction Society who consume a high-protein diet (1.73 g kg–1 per day; ~24% of energy intake from protein). Protein intake was significantly lower in the moderately PR group than in the CR group, while energy intake tended to be higher. Both serum IGF-1 concentration and IGF-1 : IGFBP-3 ratio were significantly lower in the moderately PR diet group than in the severe CR diet group, whereas fasting insulin and C-reactive protein were similarly low in the moderately low- protein vegan and CR groups, as previously reported in a smaller group of raw food vegans (Fontana et al., 2006a, 2007a). This effect of a moderate protein restriction is independent of body weight and body fat content, as serum total and free IGF-1 concentrations were lower in the moderately PR group than in the severe CR high-protein diet group, despite the PR groups’ higher body weight, BMI and body fat content. They wondered whether CR groups’ rather high protein intake (~24% of the calories from protein; 1.73 g kg–1 per day of protein) may have prevented a reduction in IGF-1 level. So they arranged for six of the CR volunteers to reduce their protein intake from 1.67 ± 0.1 g kg–1 of body weight per day to a protein intake of 0.95 ± 0.1 g kg–1 of body weight per day for 3 weeks. This short- term isocaloric reduction of protein intake resulted in a 25% reduction in serum IGF-1 concentration (from 194 ± 34 ng mL–1 to 152 ± 41 ng mL–1; p = 0.01) in the six CR individuals, suggesting that the high protein intake was preventing a reduction in IGF-1 levels in response to CR.

Hope that helps!

I have saved the full paper in evernote...you might be able to access the paper via this link I created through evernote

I can't get access to the second study, so I can't comment on it...

Here's that missing link

Thanks for the explanation and the link.

But really, looking at the details of the study, I'm still underwhelmed. 18 subjects is a very small sample easily skewed by a few outliers in one group. And then I immediately note that the "calorie restriction" group is a group 60% of which are post-menopausal women, whose weight, oddly, is not given though we are told they are not obese. Their caloric intake, however, while supposedly "calorie restricted" is a good 100 calories a day than menopausal I could eat for maintenance, at a similar BMI while that age. So are they calorie restricted, or are they merely eating properly for their age and size while the other groups are overeating a bit.


But it gets worse! How do we know what these people ate for the year of the long study where they put into groups supposedly eating different amounts of food? We don't! Participants were "instructed" to lower their calories in one group and to exercise in another. Nutritionists had them log their food for ONE WEEK, and blithely assumed that the participants were eating that way for the rest of the year. To believe that these people dutifully restricted their calories for a year is pure fantasy, of the kind only someone up for tenure in an academic department could begin to believe in.

But given that every monitored weight loss study I have ever read shows that people are almost always incapable of sticking closely to any diet for more than 3 months--a result I am sure you have observed even among participants here, it is highly unlikely that the people in the first study were eating what they said they were. So what that study proved, besides the ability of researchers to delude themselves, is hard to say.

Then we move on to the high protein/low protein comparison study. But wait, what this really was was a Battle of the Obsessional Diet Neurotics, life-extensioneers vs. fanatical vegan/raw foodists. And so it is immediately clear that we are comparing apples to oranges in this study. The groups are in no way matched. The vegans start out far more underweight, and possibly, like most vegans, in a way that is not metabolically healthy. They have low fat stores, even the women, which is often interpreted as being healthy but probably in this case is not, since we are told they are in their 50s, and we know from quite a bit of research that being underweight in our 50s is a good predictor of more, rather than less, mortality going forward. The men are downright skeletal, 7% body fat in your 50s leaves no margin of error should you become ill.

But beyond the fact that these are by no means matched groups, the fanatical vegans they have been eating a different kind of protein from the other group, which is eating dairy and meat proteins rather than all plant protein. Besides that, it is noted some of them are eating only raw food, which because it is more indigestible delivers fewer nutrients (and possibly protein) for the same amount of food. The protein the vegans eat is also likely to include quite a bit of soy, a substance with metabolic effects all its own which in vegans tends to promote leaky gut that leads to autoimmune conditions and systemic inflammation, a very unhealthy state.

So to interpret this as a study that tells us about the effects of high vs low protein consumption is to make the mistake so often made by nutritional researchers, who apparently have never heard about the concept of controlling for variables, since any difference between these groups could also be explained by the differences in the type and availability of the proteins they are ingesting, or by the size of their fat stores, since the lack of functional fat tissue in the skeletal vegans which results in the lack of a whole series of hormones that are secreted by fat and interact with IGF-1 and various other metabolic proteins. In addition, given that these participants were recruited from the ranks of true believer diet fanatics, it is very likely that there are other, psychological and physiological factors at work, too, which are what drove these people to eat the extreme diets they enthusiastically embrace.

In short, typical sloppy dietary research. I have read reams of this stuff and have found most of it to suffer from this kind of very sloppy inability to understand what it means to design a study so that you can be sure your result is due to differences in a single variable, rather than to extract the result you expected to find because you believed it would be true from data that don't in fact show that at all.

I take it you don't like Vegans

I find IF has been the best thing since sliced bread has become a rare treat My success initially with 5:2 was due to a mostly plant based foods. I would relish being vegan but seem to get awfully tired while I still have a busy schedule. Also I must stick up for the many people on this forum who have adhered to IF more than a year successfully even when we plateau. I am struggling a bit now but only after a plateau of 8 months standing did I waver. That was back was in February. Meanwhile I persist with fasting with less vigor accepting I may have to be content with 10-11kg weight loss. Maybe my body is smarter than me realising I can best operate on a BMI of 27 as I age

While all the scientific study is interesting and appreciated we are after all left to our own devices in our homes not on trials having to cope long haul in a world full of temptation. I think we do well

'IF' seems to be latest interest of Dr Mercola. He is writing on the topic again today.

http://articles.mercola.com/sites/artic ... =553301521

I like it as a simple overview to remind us of the basics and keep us motivated. Ok I am lazy but easier than rooting out Dr Moseley's book on same. He is not making any commercial angle on this and just skip his ads for other stuff.

That's really helpful @ADFnFuel thanks so much!

I think then we might recommend 1.2-2.0g/kg on fast days and 0.8-1.5g/kg on non-fast days. What about people doing the eating window though? 1.2-1.5g?

Whatever we think of the science or lack of it, behind these recommendations, @carorees, I think it's going to be a bit impractical unfortunately.

Using my stats as an example: IBW around 70 kg, gives 84-140 g of protein on a fast day. Since there are approximately 4 kcal in a g of protein, that makes 336 - 560 kcal just of protein on a fast day for me - so I'm not going to be able to eat much else within 500 cal! Atm I seem to be eating only around 30 g of protein on a fast day - and due to HIIT, my quads at least still seem to be still growing - not a very quantitative estimate of muscle mass I know.

(edited my arithmetic!)

Using my stats as an example: IBW around 70 kg, gives 84-140 g of protein on a fast day. Since there are approximately 4 kcal in a g of protein, that makes 336 - 560 kcal just of protein on a fast day for me - so I'm not going to be able to eat much else within 500 cal! Atm I seem to be eating only around 30 g of protein on a fast day - and due to HIIT, my quads at least still seem to be still growing - not a very quantitative estimate of muscle mass I know.

(edited my arithmetic!)

Luv it! Good catch - mathematically speaking!

Applying the definition of a fast day (eating 1/4 of TDEE) reduces that 336-560 range back to a do-able 84-140 kcal which leaves the remaining 416-360 calories to some combination of carbs and fats.

<lol>

Thanks, @adfnfuel, but isn't the proposal to selectively increase protein intake on a fast day to decrease muscle loss? Btw Krista Varady says this isn't a prob, but I'm not sure what her evidence is like.

I wouldn't suggest increasing protein, but eating sufficient protein. I am getting 45 g with only 435 calories. That's only 6 g less than the recommendef amount for my size at .8 g/kg. Even more useful would be to eat sufficient protein the meal before a 24 hour fast, as protein digests quite slowly.

If you eat the frozen dinners at the same calorie level the protein will be much less as they bulk them out with cheap starches, at least those available in the US. Plus they are full of additives like hidden MSG that increase hunger.