New angle on the risks of very-high-fat diets

Interesting new (mouse) study finds another mechanism by which too much fat intake can be problematic.

High-fat diet prompts immune cells to start eating connections between neurons.

For reference, the high-fat diet in question provided 60% of calories from fats, which is very, very high for mouse diets. The “low-fat” diet was not actually low relative to normal mouse diets; it was a normal mouse diet with 10% of calories from fat, but was called “low-fat” to contrast it with the very high-fat diet used in the experiment.

Notable, to me: “the high-fat-eating mice actually ate less chow and consumed the same amount of calories as mice eating low fat…” so the weight gain and negative effects seen were not, strictly speaking, from eating an excess of calories; they ate the same amount of calories, but just had an absurdly (for mice) high fraction of them from fats.


I saw that, but I couldn’t figure out whether they were distinguishing between “good fats” and “bad fats”.

They did not design the study to distinguish between types of fats; they designed it using readily available blends of chow. Their primary interest was in looking at immune response to very high fat levels - further refinement comes later, not to mention confirmation of their findings.

As always, one study is just one study.

I wonder if rosa labs could get in touch with the research team and find out what kinds of fat were used and also sponsor another study in mice using 40-50%% fat diets to see if the results repeat?

A mouse study is useful to answer questions like, “what kind of things are liable to happen when you eat too much fat?”

A mouse study is not useful for questions like, “how much is too much fat for a human?”


Just more proof that we don’t know as much as we think we do regarding nutrition and food’s effects. Today’s health revelation can still end up as tomorrow’s detriment.

Yep, but we learn a little more each time and get a little closer as well. That’s why I’ve put my money and health in Rosa Lab’s hands. I doubt I could do a better job and have no desire to keep up on ALL the research.


Why not? if a mouse study can tell us ‘‘what kind of things are liable to happen when you (meaning us humans) eat too much fat’’ cant it also tell us ‘‘how much is too much fat for a human’’?

EDIT: Or maybe RL could conduct or sponsor a human study with those percentages of fat? Atleast at some point in the future…

Sure it can. To the extent our nutrition requirements are the same as that of a mouse.

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I meant percentage wise not quantity wise.

Because we have similar DNA and chemistry, low-level processes are very similar between mice and men. But because we’ve evolved for a long time to be different species occupying different ecological niches, macro-level things - like our diets - have the potential to be quite different. Even micro-level things have the potential to be dramatically different. It’s these tiny differences that make them mice, and us humans.

At a recent panel discussion I attended, John Glendinning spent some time reminding us that “mice are not small rats.” That is, physiological and biological differences exist that make rats and mice very different species with different responses to things like carbohydrates and non-calorie sweeteners, with the consequences that mice are a much better model for human study than rats (when it comes to this specific research area.) For example, to rats, maltodextrin is the sweetest stuff EVAR and they go nuts over it (people don’t find maltodextrin to be very sweet). Meanwhile, they don’t find asparthame sweet, perhaps not at all. Mice, on the other hand, respond much more like we do.

That having been said, the evolutionary trees of mice and rats only separated fifteen or twenty million years ago.

The ancient ancestors of mice/rats separated form the ancient ancestors of primates/humans more like eighty million years ago. So we’re more differenter from mice/rats than mice and rats are from each other.

Good science demands good research models, and good scientists work hard to ensure that we understand what species make for good research models for different aspects of the human condition.

As another example… you can learn a lot about the internal combustion engine by taking apart a gas-powered weed whacker. It’s safer and more convenient than taking apart a car. Many of the general principles are the same. But you shouldn’t assume the car will run well on the same oil/fuel mix as the weed wacker.


Sounds like a high-fat high-carb diet. High-fat low-carb (keto) diets have many studies showing healthy benefits.

Animals made obese on HF (high-fat high-sucrose) and transitioned to KD (keto diet) lost all excess body weight, improved glucose tolerance, and increased energy expenditure.


I recall hearing about an elephant that was given LSD in the amount proportionate to the amount a human would get of that weight. It died.