Heidi, I think the following two videos by Dr. Peter Attia are a great starting point for people who believe in the conventional dietary approach as “balanced” or healthful. These are mostly about why the demonization of dietary fats needs to be reconsidered. After one gets that message they should be more receptive to the many other great videos explaining the keto diet by people such as Phinney and Volek.
This one is primarily about diabetes and obesity which are becoming epidemics among people following the US food pyramid guidelines. It’s short with a strong emotional punch.
And this one is a lengthier presentation about how the US dietary guidelines came to be and why they need revisiting.
People who adopt a keto diet for medical reasons such as seizures or diabetes may take a strict/restrictive approach. But one can achieve substantial benefits in weight loss, fitness and bio markers of good health without doing anything radical. The main things one should eliminate, refined sugars and starches, is common to almost all dietary approaches to health. With keto one can still eat most vegetables and many fruits in moderation with care to observe their limits for carbs, which can be learned through monitoring blood glucose and ketones via blood and/or breath. And many don’t have to change their protein intake much at all.
But it all starts with learning that the demonization of fats was a terrible mistake.