Several studies indicate that a dietary intake consisting of 60% fat is “detrimental” to health. Levels above 40% are often harmful. The ideal intake is between 20% and 30%.
Here is an important distinction: a ketogenic diet is generally a therapeutic or goal-specific tool, not a maintenance eating pattern. That changes how the “60% fat” figure should be judged.
I’ve asked AI (Claude) to find a study. Not found. Here is the answer.
Goals where it is best supported
• Drug-resistant epilepsy: the strongest indication, used for about a century, especially in children.
• Short- and medium-term weight loss: effective, but its advantage over other diets tends to fade after 6 to 12 months.
• Type 2 diabetes and prediabetes: improved blood sugar and HbA1c, often with reduced medication, under medical supervision.
• Other areas (migraine, polycystic ovary syndrome, some neurological conditions): results are still preliminary.
What this means for assessing risk
• The question becomes expected benefit versus risk, as with a treatment, rather than comparison with an ideal balanced diet.
• Risk depends on duration: a few weeks or months is very different from several years, for which data are scarce.
• The known side effects to monitor are raised LDL cholesterol in some people, deficiencies (fiber, magnesium, certain vitamins), digestive problems, kidney stones, and the “keto flu” at the start.
• Monitoring (lipid profile, kidney and liver function) is recommended, and some people should avoid it (pancreatitis, liver failure, certain fat-metabolism disorders, pregnancy without medical advice).
Studies that find harm often follow general populations over long periods. They don’t answer the question “is it useful and acceptable for reaching a given goal over a given period?” The two kinds of evidence don’t contradict each other, because they answer different questions.
Comment (LucH):
So 2 points going in the same direction: inflammation and glucose intolerance when eating high fat for several days. A result in mice, not in human beings. But whenever my body reacts heavily to a high fat meal, I take lipase enzymes… I don’t wait to see if …
