I would strongly recommend that anybody interested in fat in our diets, and in particular the 'low fat' regime that we have been recommended to eat for decades, should read Nina Teicholz' 'Big Fat Surprise'. We used to eat natural fats, lard, dripping, butter etc. All of a sudden, not for health reasons, for commercial reasons, the big food companies found a way to make 'non food products' , like cottonseed, into oils and solid fats and marketed them heavily. Along came Ancel Keys and his dodgy science, the Fat / Health hypothesis was spawned, with absolutely no Randomised Controlled Trials, based on seriously flawed and biased observational studies. And it's just rolled on and on.
I'm not convinced that for generations peasants ate a diet made up of mostly carbs, I think they ate cheap cuts of fatty meats, offal, brains, tripe etc. Eating nose to tail, a huge range of nutrients. I try to incorporate home made bone stock into cooking whenever possible and plenty of offal. Chicken livers can be incorporated into many dishes un-noticed, even by my discerning grand-children!
When you seriously reduce carbs, you have to eat something. There are only 3 food groups, carbs, proteins and fats. Carbs we want to minimise, proteins we want to eat moderately (the body can make glucose from proteins and huge quantities put strain on the kidneys) fat, provided it is natural, is a benign alternative which has been maligned and vilified for no good reason. I eat oodles of extra virgin olive oil, moderate amounts of grass fed butter (from small dairies when I can get it but if not Kerrygold, which I am told is made from cows that are pastured for longer, which could be rubbish but who knows) and a little lard / dripping, and of course I no longer choose leaner cuts of meat, I look for marbling for flavour, taste and texture, if it's organic, even better.
When you buy a bottle of low fat mayonnaise, it isn't half empty. What has replaced the fat? Carbohydrates. It's not full of nothing (although it could have non food fillers, like wood pulp or 'wallpaper paste'). For me, Low Carb High Fat absolutely goes hand in hand. No I don't eat spoonfuls of butter, I don't drink mugs full of bulletproof coffee, I eat natural, unprocessed, real food that my great grandmother would recognise, prepared carefully and nearly always from fresh, raw ingredients. And nobody will ever convince me that it's not healthy, it has restored my health and my vitality, enabled me to lose 40lbs+ in weight, totally eliminate high blood pressure, GERD and get rid of all medications, as well as taking away the threat of diabetes. The science has moved on, why is the mention of High Fat seen as a problem in the HFLC diet? It is the core of it, it is the key to its success, if you don't understand that, you don't understand it.