Since this diet is low to zero carb it's also appetite suppressing which makes it hard to gain weight/muscle.
Not necessarily. Yes, this diet is very appetite suppressing. However, I haven't yet heard anyone on this diet complain about not being able to gain weight. The Asian girl you posted and the white girl I posted both gained a healthy amount of weight on this diet.
What some people, usually women, on this diet report is that they can't lose weight or that they actually gain weight when they are trying to lose it.
What they are told to do in order to stop gaining weight and start losing weight are the same things you could do to gain weight on this diet. They are told to not avoid fat in whole foods, but at the same time to not add more fat: Don't cook your fatty meats in butter, bacon grease, lard, beef tallow, etc. Don't melt butter or bacon grease on your steaks or burger patties before you eat them. Don't melt butter in your coffee, if you drink coffee.
Doing those things could actually add lots of calories from fat and very easily create a calorie surplus. As we all know, fat has more than twice the number of calories per gram than protein and carbs.
Another thing you can do to gain weight on this diet is to finish your meat heavy meals by snacking on pork rinds, peperoni slices, boiled eggs, very low carb cheese, and/or drinking heavy whipping cream with a drop of vanilla extract and your favorite artificial sweetener.
you also have to have very low protein to stay in ketosis, not ideal for a bodybuilder
anyone over 100gms protein will be lucky to be in ketosis
joswift brought up a good point about protein on this diet, although I disagree with his 100g limit. Another reason why a carnivore diet is not ideal for a Mr. Olympia level bodybuilder is because eating too much protein will raise insulin levels, nowhere nearly as much as carbs, and somewhat suppress ketone production. But this is not an issue unless you want to stay in ketosis 24/7.
Many carnivores I know consume 1g protein per pound of "desired" body weight and they seem to be doing fine gaining and maintaining muscle mass while staying in ketosis.
In theory, consuming very little to no carbs and very little to no plant-based foods allows your body to absorb animal protein much more efficiently, so you may not need nearly as much protein on this diet as others do.
Within a food source, other components alter the overall digestibility of the proteins. Some plant foods contain anti-nutritional factors that decrease protein digestibility. Legumes, cereals, potatoes and tomatoes contain inhibitors that reduce protein digestibility by blocking trypsin, pepsin and other gut proteases (Savelkoul et al., 1992; Liener, 1994; Friedman and Brandon, 2001). Cereal grains and legume seeds contain tannins (polyphenols) that bind strongly to dietary proteins and digestive enzymes, thus inhibiting protein digestion (Jansman, 1993; Jansman et al., 1994). Nuts, seeds and grains contain phytic acid (Lott et al., 2002), which chelates minerals such as calcium and zinc. As these minerals are necessary cofactors for digestive enzymes (e.g., alkaline phosphatase, carboxypeptidases and aminopeptidases), phytic acid in foods reduces overall protein digestibility (Ryden and Selvendran, 1993). Many legumes and alliums contain saponins, which form part of the plant’s defense system (Francis et al., 2002). These saponins reduce protein digestibility by forming saponin-protein complexes (Potter et al., 1993). Likewise, many plant proteins are surrounded by complex carbohydrates (non-starch polysaccharides or fiber)—often as cell wall components—that can impede enzyme access to the proteins (Duodu et al., 2003). The abundance of anti-nutritional factors and complex carbohydrates in plant protein sources likely explains their overall lower digestibility than that of typical animal proteins.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4927412/
