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New Poliquin Article on Intermittent Fasting: The Pros and Cons of IF
http://www.charlespoliquin.com/Artic..._Fasting_.aspx
He argues against IF for athletes, anyone desiring to build muscle mass, and women of reproductive age... an interesting read.
Jordan - any thoughts?
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I don't think IF is optimal for anyone UNLESS it is the magic bullet that gets them to comply so in that sense, I agree with Poliquin's editorial staff. On the other hand, they're wrong about insulin and protein dosing to optimize results but overall they're recommendations are fine.
Here's the hierachy: macros> food quality > food timing
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Yes, I wondered specifically about the claims about insulin... which part particularly do you disagree with?
"Irregular eating patterns influence insulin and blood sugar health. The research is not conclusive on this issue—men tend to have improved insulin health, women have worse. The obese in both genders tend to improve insulin health, but other factors are affected such as blood pressure, and fasting, just like caloric restriction, is considered unsustainable by many scientists.
However, don’t believe the hype that intermittent fasting necessarily improves insulin sensitivity. One study in the journal PLOS One compared insulin and glucose over 3 days in response to an intermittent fasting model and regular meals 5 times a day using a diet of 55 percent carbs, 30 percent fat and 15 percent protein. Results showed that the intermittent eating model produced significantly greater spikes and troughs of insulin and glucose, indicating a biological milieu primed for insulin resistance over time.
Limiting high-glycemic carbs is the real key to insulin and blood sugar health. A study that compared eating 3 high-carb, 6 high-carb, or 6 high-protein low-carb meals a day found that blood sugar was highest in response to the 6-carb meals, followed by the 3-carb meals, whereas insulin was the same in both carb models. The high-protein meals produced dramatically lower insulin and glucose levels."
Last edited by Jordan Feigenbaum; 02-13-2013 at 10:14 AM.
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One- define insulin health, is it insulin sensitivity? If so, low carb actually reduces insulin sensitivity. If it's something else, define it Poliquin and friends.
My main thing with insulin, especially as of late with everyone getting their pubmed phd's, is that it's not a bad thing at all. People think if you release any amount of insulin you're going to get fat, turn into a diabetic, and see your Fran time increase. It's not like any release of insulin stops fat burning body wide. A very large release of insulin for a long period of time would be bad, of that there's no question, but insulin does some pretty cool things like increase protein synthesis, shuttle stuff into muscles, etc.
Also, basing anything off the Glycemic Index is foolish, as those numbers were determined by eating only carbohydrates in a fasting state, i.e. not a mixed meal. Finally, the last sentence of the above quote is exactly what we'd expect, yet it doesn't mean anything with respect to body comp, performance, and an individual's nutrition plan.
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The term insulin sensitivity is context specific. What doing low carb for the long term will more specifically do is to lower glucose tolerance do to down regulation in the enzymes and intercellular components required to transport glucose into the cell (in response to low exposure). As almost all the ways insulin resistance is investigated in the literature are in a hyperglycemic context those data lack applicability to someone doing low carb. I agree with the rest of your position though.Originally Posted by Jordan Feigenbaum
It is also ridiculous to suggest that higher peaks in insulin and glucose in the IF group are related to anything other than a larger bolus at the time the fast is broken, which is the hallmark of IF protocols.
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Exactly, but it's still being "insulin resistant". I don't think it's a bad thing, just more of a using the correct terminology. Hell, in sepsis you also become very insulin resistant right away. With low carb, basically yes the enzymes are downregulated a touch, the glut receptors aren't as prevalent on skeletal muscle cells, and you upregulate fatty acid oxidation and ketone utilization. Make no mistake, you'll be worse at using carbs and shuttling them into skeletal muscle when you go low carb. This isn't a bad thing per se, but something to think about if you're going to do a CKD type diet meaning your carb refeeds should be moderated optimally.
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I'm just curious as to what your idea of the optimal carb re-feed would be. Obviously it depends on various things, but I'm just looking for the principles or a rough idea.
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Depends on how lean the person is, how low the carbs are, frequency of refeeds, LBM of the person. Hard to say in general, especially when keto and low carb aren't really the same thing ya know? Basically, if someone were doing ~100g carb/day I'd like to see about a 250-300g carb refeed. If someone were full on keto (<50g/day) it'd be more like 200g.
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But that’s my point – I don’t think it’s appropriate to blanketly refer to that a state of “insulin resistance.” The term tends to be used almost solely with respect to the ability to lower blood glucose after exposure to dietary carbohydrate. However, more accurately it also refers to the inability of insulin to inhibit adipocyte lipolysis and hepatic glucose production, two things that tend to precede problems with muscle glucose uptake and directly contribute to these problems. What you are talking about is an adaptive decrease in the intracellular infrastructure responsible for promoting glucose uptake that only presents when exposed to a carbohydrate bolus that, due to the nature of the adaptation, rarely occurs. I think you are smart to point out what implications this will likely have for carb refeeds, but there is no implication for either alterations in fatty acids in the portal circulation or how the liver responds to them. There is no implication for the promotion of a more proatherogenic lipid profile – the things that make insulin resistance damaging. When you consider that a great many number people who adopt such dietary practices do so because of concerns over their insulin sensitivity and diabetes risk I think it becomes even more important to make the distinction. What we are talking about is a form of glucose intolerance that occurs independent of changes in insulin sensitivity, but mimics the response seen in pathological insulin resistance under conditions that are rare in the individual in question.
Anyway, this is my second nitpicky discussion on insulin resistance and glucose uptake in two days, and that is likely at least one too many.
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You noted about how lean the person is, and I had a question stemming from that. Does it matter how fat a person used to be? From what I think I know, adipose cells hang around for ~10 years after being emptied, so is it possible that heavy re-feeds could cause the body to restore these cells with fat?
Also, does a person have to be in surplus for the refeed to work? I do the keto option(~10-15g/day), and sometimes I have a number of refeeds in the 200g range, but I don't go over maintenance cals by keeping them relatively low fat. Will leptin levels still be reset/spiked from this, or do you need an attendant caloric surplus for the refeeds to work?
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