Discussing/researching nutrition/diet is like doing computer performance analysis. Performance gains & losses by flipping some switch is magic to those unfamiliar with the mechanics, but obvious to those with an understanding of the lower-level mechanics. (e.g. loop unrolling being faster...)

There has been a tremendous corpus information that has been accruing about nutrition and metabolism, unfortunately the information is not in vogue and thus relegated to the dusty corners of libraries or the internet. Many times the data or factoid is conflated with sensational information and loses its credibility.

There are definitely several caveats that participants are usually not cognizant of when adopting a higher-protein/higher fat diet, but they usually end up making generally correct decisions which lead to the desired benefits. The caveats to keep in mind are:

* consuming oxidized fats (through high heat: fried foods) would severely increase cardiovascular risk. These fats tend to not be easily broken down the way other fats are. Restaurant oil is being constantly filtered and reused makes for highly oxidized fats. Going ketogenic with deep-fried bacon would probably accelerate the inevitable heart-attack.

* hydrogenated oils are were modified to be stable as it acts as a preservative in foods and increases shelf life. However, the stability of hydrogenated oils compared to regular oils means that the body can not easily break down the hydrogenated oils. These fats are also not good for the body to consume.

* Most oils & meats are rich in omega 6 fats, but it is the omega 3 fats that are carido-protective. Grain fed cattle & fish (farmed) skew very high for omega 6 with very little omega 3s negating their benefit for consumption. Grass fed and wild-caught fish have around a 50/50 omega 6/omega 3 ratio, which is the ideal ratio to target.

Carbs can be just as filling as protein & fats and lead to weight loss. However, carbs heavily rely on fiber to not spike glycemic load. The glycemic load of carbs will spike insulin and all the other bad effects of prolonged insulin exposure. Since glucose gets stored as glycogen in the muscle & liver, once the glycogen stores are filled up, glucose tends to not have anywhere to be stored. Excess fats can be stored inertly, indefinitely and in almost limitless quantity. Glucose doesn't have this benefit, thus it must be quickly taken up.

Insulin & Hypocretin/Orexin appear to have an inverse relationship. Insulin release shuts down the hypocretin/orexin neurotransmitters which are responsible for wakefulness and hunger. The extended insulin spike brings on drowsiness, but once the insulin goes away from lowered blood glucose levels, wakefulness and hunger return. Orexin is what is responsible for waking one up in the morning when the eyes start receiving sunlight. The insulin spike and orexin going back and forth become a non-virtuous cycle of hunger followed by eating, followed by more hunger, so on and so forth.

People who have depleted their muscular glycogen (e.g. person running marathon, lifting heavy objects, fasting) can take a huge spike of sugar/glucose and there will be a large amount of glucose uptake possible in parallel by all the glycogen-depleted muscle cells. In the agrarian society, this used to not be much of an issue as the manual toil tended to use up the glycogen available, but in today's office society, smaller muscle mass (smaller glycogen stores), along with sitting all day tend to keep insulin spiked way longer, which overworks the thyroid's generation of insulin and leads to insulin resistance.

It used to be that diabetes and obesity went hand in hand, but the increasing prevalence of skinny type-2 diabetes points to a similar problem as obese type-2 diabetes. Blood glucose & insulin are spiked too high for too long with no where to go. Ironically, many obese people tend to have a decent amount of muscle underneath their fat from carrying all the fat around and end up being able to consume the glucose faster than the skinny type-2 counterpart.

High fat, high Protein, low carb tends to cut out the high-glycemic items (junk food, soda) and the surrounding culture ends up promoting more vegetable intake, thus the benefits can get generally realized by the adopters of low-carb lifestyles.