One of my favorite radio stations (Sirius XM Pops) is on a Grieg kick, and I suppose I am too.
There's a lot to like about the study, which tracked mood for folks on a 41% fat diet (controls on the average fat consumption in the UK at the time) and a 25% fat diet for several months. They were given three meals and two snacks with enough calories to keep them at a steady weight. Though it is small (20 people), all food was provided and detailed food diaries were kept for every morsal consumed. All 20 finished the program, but one was excluded from the results because she had a very serious personal tragedy which would have affected her mood. The twenty subjects had no previous psychiatric history and at the beginning of the study had no major stressful life events going on.
Hostility and anger increased significantly among the low fat dieters, and depressed mood decreased among the 41% fat dieters while it increased among the low fat dieters. Tension and anxiety also increased among the low fat dieters. All in all, things did not look rosy for reducing fat to, well, unnaturally low levels.
Editorial comment: As most of you will know, I am fairly macronutrient agnostic, and I've read reports of people who are plenty happy eating low low fat, and others who are content eating very low carb. My main beef with the "official" low-fat and counting-happy guidelines is that they encourage the consumption of processed food. It's a lot easier to calculate points and calories when you are eating SmartOnes 6 times a day. Not so easy with pastured eggs of different sizes and cooking all your own food. Of course I haven't tried to calculate calories since the advent of all sorts of helpful apps for that purpose, but it is not something I'm particularly interested in pursuing. I'd far rather control portion size and eat from a long list of healthy "real food" options than track every bite. There are others who find restricting food groups leads to anxiety. I would say, don't fix what ain't broke. If it works for you, keep doing it. If it doesn't…look for another solution.
I also don't see much benefit to chasing very low carb to the extreme unless you have dementia, seizures, brain cancer, or another neurological condition that may benefit. I don't believe VLC is the fountain of youth, an evolutionary precedent, or particularly advantageous to whole body health compared to a whole foods diet comprised of mixed macronutrients (and "cellular" carbohydrates). A really good paper has been circulating recently, which I saw first via the one and only Robb Wolf. It is free full text! Google the name or download from the link. Well worth the time.
The discussion and introduction to the paper I linked from 1997 was illuminating. The authors noted that folks with low cholesterol have a higher tendency to die from suicide, violent death, and accidents. (I review much of the literature in this classic post). We also see a statistically significant increase in depression and hostility with any non-statin cholesterol-lowering medicine (for whatever reason, docs in my area are starting to prescribe fibrates to lower triglyceride numbers, and I'm not too thrilled). The statins seem to be a wash for most, though I've certainly seen a few clinical cases where they seem to worsen depression and even psychosis. (In monkeys, diet promoting low cholesterol significantly increased "contact aggression" compared to a typical diet.)
In the small pilot study, mood and irritability and such seemed independent of cholesterol levels, suggesting that maybe the links between low cholesterol and violence/suicide in the general population might be a general sign of low-fat diets rather than a straight-up link between cholesterol levels and behavior per se. But who knows. As expected, the low-fat diet decreased HDL, but not LDL or triglycerides too much.
The take home? Conservatives, go Mediterranean and glop on the olive oil. Rebels, eat your chicken skin and the fat that is left on your steak. It's all right. Your brain might even thank you.
Image credit
That study seems pretty clear in its conclusion. Although it would be nice to see more studies like that of larger size and longer duration. The other fat and mood studies are confounded by weight loss. People go on a low fat, low calorie diet to lose weight and their mood improves, but perhaps they attenuated inflammation or improved dietary quality in other ways, or were happy because they lost weight or the people who conducted the study were extra nice. In these studies they still had a depression score that's too high for my liking.
ReplyDeleteEven though that study needs replication we can still have good reason to believe that fat restriction is less than ideal because of the mechanism that Emily described in the post Fat And Happy. It seems to be an acute effect that is tied to neuropeptide production, or maybe that and something else.
If someone thinks that fat like totally kills them and can have a good mood without it then all the power to them, but when we're talking about generic recommendations for an entire population, particularly those at risk of mood disorders, it becomes clear that low fat diets have not been demonstrated to be free of side effects.
SpreadBerry's (sorry, Spreadbury's) Cellular paper is very interesting.
ReplyDeleteFor me, it adds another (plausible) mechanism to Lindeberg's version of Gardening Paleo rather than Cordain's rampant Grokking.
I, too, am a macro agnostic. I've been a Hearty Peasant food eater for decades, and include lots of KerryGold and Irish potatoes in that - of course, the total volume is mediated by hunger.
"I eat when I'm hungry,
And drink when I'm dry,
And if moonshine don't kill me,
I'll live till I die."
http://www.youtube.com/watch?v=El3a-1bSIZM
Slainte
I loved the Spreadbury papper as well. I thought the background section is one of the best introductions I have ever read to the current scientific understanding of paleo diets. I liked how they incorporated ideas from so many disciplines -- microbiology, immunology, dentistry, endocrinology, etc. This is the sort of thinking that will be needed to figure this stuff out.
ReplyDeleteI would like to hear what a microbiologist would say about their hypothesis, that acellular carbs cause disease by altering microflora. This did not seem terribly convincing to me. For example, under their theory, you might expect populations that have evolved higher levels of salivary amylase to show higher levels of dental disease, even if they stick to an ancestral diet. You could also try sprinkling wheat gluten on your potatoes and see what happens over time. Per Spreadbury, the potato+gluten meal should be healthier than whole wheat bread. Should be easy enough to test.
Greg, I agree the mechanism is a little hinky. On the other hand, I can see how historically our guts never had to cope with quite the amount of straight up starch that comes from processed carbs, boom, right on the vulnerable parts of the gut. The inflammatory cytokine story was the most interesting. The Spreadbury paper should be a template for all sorts of interesting experiments, perhaps using the same strategy as Ludwig's paper, but let's compare processed diets of the same macronutrient composition as all whole diets (add benefiber or something). That should tell us once and for all if a calorie is indeed a calorie (as I've heard Willett endorse) or the package realy matter. We certainly know the answer in rodents. I want to see it in humans.
ReplyDeleteOkay, now I do not feel so bad about eating the skin of my chicken.
ReplyDeleteA boiled potato is about 22% carbohydrate. A Macdonalds fry, according to the packaging, is 44%.
ReplyDeleteRight there, you've crossed a line. 44% is about bread density.
The McDonald's fries, potato chips (and also Orida and hash browns and other quick commercial brands) are dehydrated and flash fried. Very different from baked potatoes, or home fries.
Delete"The finding that glucose consumption elevates NFκB and inflammatory pathways
ReplyDelete57 without producing changes in LPS or TLR4 levels is important evidence that a glucose-induced non-LPS/TLR4 inflammatory pathway exists." Spreadbury.
Yes, that is cool indeed. But is it due to an overwhelmed microbiota, flash fed glucose, or some other mechanism?
DeleteAaron Blaisdell tried to comment but it didn't go through, so here is his comment:
ReplyDelete"Emily, what do we see in rodents, that a calorie of processed food is not equal to a calorie of whole foods? Do you have references for this? I'm about to start a study that looks directly at this question, but haven't found in the literature any exact comparison of food quality while holding macronutrient content the same."
Aaron, what I am recalling are some studies mentioned by Chris Masterjohn and Stephan Guyenet that didn't explicitly set out to measure comparisons of whole vs. processed diets, and now that I think about it, they were different macronutrients. I don't recall ever seeing a study that set out explicitly to measure processed vs. whole with care being taken to hold macronutrients, fiber, etc. the same and it sound like an interesting one.
We were required to watch this video on sugar for our community/public health nursing class. He is a physician & disproves the cholesterol causes CVD theory, like you and other paleo people have mentioned! http://www.youtube.com/watch?v=dBnniua6-oM Sugar: The Bitter Truth. I'm only 30 minutes in but it's been great so far.
ReplyDelete