Hi Orakar, as someone who has also picked up on some of the negative effects of IF in the research, maybe I can give some opinion.

Fasting appears to effect a number of hormone and chemical levels in the body. Low IGF1 has been linked to positive cancer results. Fasting also helps to lower and improve insulin responses.

The positive brain results quoted in the original Horizon were based on the work of Mark Mattson. From what he has said, IGF1 was not involved – he believed it was another hormone, BDNF which gave benefits.

The study you quote does not appear to involve fasting. It may be that while low IGF1 is (possibly) bad for the brain (but maybe good for other parts of the body) that the overall results of fasting (and BDNF) have a net positive effect on the brain.

I’m not clear what would cause a low IGF1 if not fasting. It could be that low IGF1 without fasting is a sympton associated with some other cause and that the other cause is affecting the results but that would be very speculative.

For those that are trying to lose weight, I wouldn’t worry about this research. For those who need to fast to maintain (like me) I wouldn’t worry either. That said, my understanding is that there is very little research into fasting for those who aren’t overweight.

HTH, David

I’ve read a few entries on this forum reporting IGF-1 levels tested before and after starting 5:2. None of those reports indicated a reduction in IGF-1, all showed a slight or moderate increase. I’m not sure that there hasn’t been any reports of IGF-1 reductions or that there couldn’t be a decrease, as there was for Dr. Mosley (at least in the one test he did on the Horizon program), but I’m not aware of any data either that indicates you should expect a decrease in IGF-1 from intermittent fasting.

On the Horizon show, Dr. Longo indicated that longer fasts would lower IGF-1. He also talked about people who, because of a mutation, completely lack IGF-1 and are consequently of dwarf stature. Dr. Longo stated that none of these people has ever gotten cancer. He didn’t mention that they had cognitive problems, but if low IGF-1 has negative effects on the brain, then these folks should show that effect. I can’t remember the name of the dwarfism. I’ll try to find it.

Since 1940 there are 75,000 synthetic chemicals put in our food chain. It isn’t about one aspect of a study it’s about overall health. About the processed non processed foods we eat, the amount of refined sugar consumed. Eg if we have mercury fillings can cause brain damage so many aspects to pollute our bodies. Fasting gives our bodies a chance to repair itself. 4/5 generations ago in my family people lived till average 80-90 with no modern day diseases ( blood pressure, diabetes strokes heart attacks cancer etc) my mother had a stroke at age 56 is diabetic and has high blood pressure.

How else does a person repair/detox the entire body?

For 3 years I have not had a cold/infection ever since I started drinking every hot water lemon and ginger every morning on an empty stomache. Nutrients unrefined unprocessed foods that are cleansing plus fasting = healthy body.

I have scanned through the complete forum for 5:2 dieters who have had done IGF-1 lab test before and after some month of the diet. None of them have lowered there IGF-1 by the 5:2 diet itself. I have gotten my lab results on Friday after 2 month of 5:2 and there was virtually no change on IGF-1 which was for me a bit of a disappointment as I was hoping to get IGF-1 down.

From what I read and seen in the studies so far is that IGF-1 gets lower if you lower your protein intake.

Cyberduck – Skinny people can get Diabetes. My maternal family mostly have bird size bones and are naturally slim – in fact most have really low BMI and cannot get fat even when trying. Quite a few also have developed Type II diabetes. My paternal family on the other hand are all large boned, tall and prone to obesity and most also have Type II diabetes. So I figure I’m a sitting duck from both sides so very keen to keep BMI low and do everything else possible to avoid Diabetes.

I had IGF measured yesterday so will be interested to see results in a few months. Was also eating fairly high levels of protein daily so may see a decrease as I have lowered protein to no more than 0.8g per kg – so for me that is about 60 when at goal mass and now about 80g per day. Way less than the 120 – 200g I have been doing for years.