The FastDay Forum

But meanwhile (with the NHS performing 60,000 gallbladder removal operations per annum, and 103,000 people in the UK suffering heart attacks each year, and 94,000 people dying of coronary heart disease annually in the UK) I, personally, think it highly inadvisable to risk a high-fat diet OR a high-sugar diet. And that's just my opinion, nothing more.

[Statistics from NHS and British Heart Foundation]


It has been argued that one of the contributary factors to gallbladder removal is a low fat diet. This is because the gall bladder's bile secretions respond to the presence of fat in the diet. When dietry fat is no longer present in sufficient quantities the gall bladder is no longer being flushed and the bile within it becomes static. This, it is thought is how gall stones develope. When fat is re-introduced into the diet after a lengthly absence i.e fried breakfast, bacon sandwich,avocado etc the gallbladder responds and the gall stones can then enter the bile ducts.Fat is then seen as the culprit.

Sugar isn't the only component of a low fat diet. We are advised to base every meal on starchy carbs which contribute to blood glucose just as much as refined sugar. It may be that the heart atacks and coronary heart disease are down to the very high carbohydrate diet that is currently recommended by the medical profession. And that's just my opinion, nothing more.

[quote="itadakimasu"
It has been argued that one of the contributary factors to gallbladder removal is a low fat diet. This is because the gall bladder's bile secretions respond to the presece of fat in the diet. When dietry fat is no longer present in sufficient quantities the gall bladder is no longer being flushed and the bile within it becomes static. This, it is thought is how gall stones develope. When fat is re-introduced into the diet after a lengthly absence i.e fried breakfast, bacon sandwich,avocado etc the gallbladder responds and the gall stones can then enter the bile ducts.Fat is then seen as the culprit.[/quote]


This is true, at least in my experience. Several years ago I went on a vlcd (Lighterlife) - at the time I was in good health since it was a requirement at the commencement of the diet to obtain your GP's consent and he did a full blood analysis including fasting glucose etc. I lost a significant amount of weight and stayed on the diet for around 2 months but it was very expensive. I resumed eating solid food gradually and carefully but within a couple of weeks I began to experience agonising abdominal pain.

To cut a long story short, I ended up having my gall bladder removed, followed by pancreatitis because of gallstones flushed into the common bile duct. Truly terrifying and horrendous - prior to the vlcd I had never experienced gallbladder problems. I was told the cholecystitis was a direct result of a low fat/no fat diet, in exactly the way described by itadakimasu above. There is a great deal of scientific evidence to support this which I brought to the attention of Lighterlife (this is a whole different story that I won't bore you with now) and it made me wonder why a low fat diet was encouraged by the NHS when they were aware it contributed to gall stone formation.

Thank you Phoenix and Marlene for those personal stories, both alarming and alarmingly contrary!

So where does that leave us? High fat diets can be dangerous (per Phoenix's family experience, and this is very much the mainstream view), and low fat diets can be dangerous (per Marlene's own experience). And there are good reasons for thinking that high protein is dangerous. VLCDs are dangerous yet of course being overweight is dangerous. Confusing!

For the moment I am thinking the safest is 'moderation in all things'. So I will try to cut down on the high GL stuff (sugars especially, even chocolate ), have less red meat, eat more greens (which fortunately I have always liked), but still have chicken and fish and eggs and bread and oats and (a few) potatoes. Enjoy alcohol but not on weekdays. Fast for (1 or) 2 days per week. And break all these rules quite often...

I think Peter Attia had a tee-shirt printed with 'MODERATION: the only thing that should be done in moderation'!

Clinical interventions to reduce carbohydrates (inevitably increases fats) yield improvements in cardiovascular risk factors http://www.ncbi.nlm.nih.gov/pubmed/22905670

A systematic review of evidence for dietary / coronary interactions concluded "Insufficient evidence (≤2 criteria) of association is present for intake of supplementary vitamin E and ascorbic acid (vitamin C); saturated and polyunsaturated fatty acids; total fat; α-linolenic acid; meat; eggs; and milk." http://archinte.jamanetwork.com/article ... id=1108492

Low fat diets do indeed challenge the cholesterol disposal route via the gall bladder. The number of gall bladder removals is perhaps a function of the low fat eating mantra.

PhilT - there is an interesting difference in response to the 'prudent' and 'western' diets between Europe and the US in the second link above - it appears that the prudent diet does not suit Europeans, while the western diet does. Could this be due to the historic american obsession with fizzy drinks, and will the UK be catching up now? Also, heavy consumption of alcohol seems to confer benefits from CHD - but I guess something else (cirrhosis?) gets you first...

We don't have HFCS or a corn industry pushing extra caloric sweeteners which may help avoid US style soft drink consumption levels. The alcohol connection often pops up - usually red wine - inevitably followed by a study with the opposite conclusion. As you say, we die of something eventually.

The 'prudent' diet used in a RCT of secondary prevention was 30% calories from fat in both control and experimental groups, but a shift to polyunsaturated omega-3 fats/oils delivered a significant reduction in subsequent heart issues and mortality http://www.ncbi.nlm.nih.gov/pubmed/7911176 which to me says the type of fats and oils is as much an issue as the quantity.

As I said somewhere, we evolved in an environment where fat, carbohydrate (especially sugar) and salt were hard to come by. We crave them for that reason but our bodies are not able to handle them. I believe that a true Paleo diet would consist of mostly vegetables with small amounts of meat/fish/eggs and very little fat, sugar, grain and salt. And of course variations in availability resulting in feast and famine.

Of course I'm not following my own advice...(apart from the feast and famine bit)

It's not clear that fat was as scarce as you say. It's true that game meats such as venison are very lean, but total carcass fat content, including brains, bone marrow, and kidney fat, made more fat available. We can assume that hunter-gatherers didn't waste any of it. If they wasted anything, it would have been the lean muscle meat they couldn't consume, which would have been given to the dogs.

In temperate zones, carbohydrate would have been much scarcer, especially prior to cooking. When you watch these "survival in the wilderness" types of tv shows, the striking thing is how little there is to eat, unless you can trap/kill an animal. Wild roots and tubers are around, but they are very fibrous and tough, not like domesticated potatoes and yams.

Michael Mosley suggests only lean meats and eggs and green veggies on fast days. Eat "responsibly" on feed days. The whole diet is pretty simple. It is not meant to confuse or overwhelm you.

I eat what I like on feed days. If I want French fries, I occasionally order them, but I don't do it all the time. The whole point of the diet is you don't want to restrict or deny yourself too much, because that is why so many diets fail.

[carorees]

There is a school of thought that humans became so successful because they learned how to eat things that other animals couldn't and so were not competing with other species directly. Think of the foods that people eat that have to be processed to make them edible/nutritious...maize, many tubers, certain beans, possibly many green vegetables.

Perhaps the fat question is how much of the fat in game is saturated fat? I still think that fat was relatively scarce, like sugar and salt and this drives our desire for such foods.

Discovering fire, learning to cook and being able to sweat and run seem popular explanations for our success - we can catch antelope by running them into the ground as they overheat.

Coming from 54 deg N of the equator most of what grows needs to be eaten by something that you then kill and eat yourself - or steal its eggs.

Game meat from deer is 7% fat of which 3% saturated. Wild duck 15% fat of which 5% saturated. Hazelnuts 70% fat of which 5% saturated.

The thing that drives our desire for fat is that we need to eat it - essential fatty acids - unlike carbohydrates.

There is a school of thought that humans became so successful because they learned how to eat things that other animals couldn't and so were not competing with other species directly. Think of the foods that people eat that have to be processed to make them edible/nutritious...maize, many tubers, certain beans, possibly many green vegetables.

Perhaps the fat question is how much of the fat in game is saturated fat? I still think that fat was relatively scarce, like sugar and salt and this drives our desire for such foods.

There is evidence that the expansion of the human race coincides with the extinction of megafauna. A possible explanation is that our ancestors hunted them to extinction. The larger the animal, the greater the percentage of carcass fat, since fat has structural and insulation properties as well as being stored energy. So, on this view, we evolved by systematically exploiting the best sources of fat.

There's quite a bit of saturated fat in game, since the metabolic mechanism is the same as it is in us. When carbohydrate is converted to fat in the body, it is 98% palmitic acid, a saturated fat. Over time, some of that fat is desaturated to palmitoleic acid, a monounsaturated fat, leaving a blend of roughly 45/50% saturated and mono, and 5% polyunsaturated. Those numbers vary from one species to the next, but not by that much.

It's interesting that we have taste receptors for salty and sweet, but none for fat. In fact, fat in itself is relatively tasteless, but it makes other things taste better, which is why low-fat foods taste like crap.

Many of the foods that we made edible required fire to do so. Maize, of course, doesn't count because it was a New World food anyway, and our species was fully evolved before arriving in the New World. The same goes for potatoes. Beans are an interesting case. Most are toxic unless cooked, but some can be made edible by soaking, which would have been possible for hunter-gatherers. Of course beans, like nuts, would be a seasonal food anyway.

Plenty of leafy greens are edible raw, but they are calorically very poor. Gorillas have much longer guts than we have, and they can survive eating little else but salad greens all day. If we tried a "gorilla diet" we'd be sick and malnourished in no time. In zoos they feed gorillas a lot of fruit, but in the wild they wouldn't get nearly as much fruit, since they're not terrific climbers. In the wild they have to eat leaves and shoots--low-density food. Because it's low-density they have to eat pretty much continuously all day, which is exactly what they do.

Human beings appear to have differentiated themselves in grasslands and temperate zones. That's why it's so revealing to watch those survival shows. If you dropped me into a Pennsylvania forest or a Nebraska prairie at random, there would be very little for me to eat unless I got lucky and fruits, berries, or nuts were in season. The weed purslane grows everywhere, and it's edible, but I'd have to eat buckets of the stuff to get a few hundred calories. Wild tubers are out there, and maybe I could pound them with rocks to make them edible, instead of breaking my teeth on them, but they're not that plentiful. To survive for very long I'd need to find some eggs, catch a fish, or kill something.

And I'd better be good at fasting!

PhilT is correct that the dietary requirement for carbohydrate is zero. I've done zero-carb experiments on myself for over two months at a time. It's tedious but didn't harm me in any way. The only person I know who claims that there is such a thing as a dietary requirement for carbohydrate is Paul Jaminet, author of The Perfect Health Diet. He argues that inadequate carb intake leads to dry eyes and impaired production of mucus throughout the body, making us more susceptible to infection. He claims that we can't make enough from protein to get the job done right. As far as I can tell, his thesis, though interesting, remains unproven.

I've done long periods of low/no carb dieting and never noticed anything like dry eyes or impared mucus production. I didn't get any sort of infection either.

I wouldn't say that doing low carb is tedious, there isn't anything difficult about meat or fish and veg or salad. The tediousness comes when you go to a restaurant and find that there are very limited no carb options or you order something that doesn't state carbs and it arrives with a portion of chips or new potatos.

He actually said

I've done zero-carb experiments on myself for over two months at a time. It's tedious but didn't harm me in any way.

I think it was the zero that was tedious.

I'm glad you're paying attention PhilT