I'll deconstruct this piece by piece, because there's a lot of subtle wrongness in this paragraph.
"MCT's can be of great use on a diet high in complex carbs because of its protein sparing effects.
The "protein sparing effects" come from consuming a diet rich in triglycerides, not from MCT in particular.
But when on a no to low carb program, the body, instead of using the long chain fatty acids that make up most body fat, uses the MCT's.
True. But guess what: when you eat any food, your body uses the new calories for food instead of body fat.
He's also greatly oversimplifying the body's fat manipulation. Long-chain-fatty-acids are not the be-all and end-all of fat metabolism.
The body ends up bypassing the very metabolic processes that the diet sets up: to burn its own fat and use the long chain fatties as a primary energy source.
Sure. Until they're used up. Then it's back to body-fat-burning, without a hitch... UNLESS you are consuming too much protein, in which case you'll see some muscle catabolism as well.
The REAL problem is consuming too many MCTs in a fasted state (i.e. more than a Tbsp, gave or take per individual), because this results in excess ketone production, which stimulates insulin release, knocking you out of that optimal body-fat-burning metabolic state.
But even that doesn't really matter, because the same thing happens as soon as you eat a meal consisting of any more than about 15g of protein -- which stimulates insulin as well. The presence of insulin prevents adipose tissue from releasing fatty acids to be burned as fuel.
But as soon as insulin goes back down -- which should happen regularly and fairly quickly on an ULC diet -- fatty acids come back out of fat cells to fuel the body.
This guy is talking as if there's some way to avoid burning consumed calories as fuel. Unless you are fasting, this is just silliness.
The long chain triglycerides utilized in this diet also have several advantages over the MCT's. They have an even greater protein-sparing effect than the MCT's.
Again... he's talking about the benefits of consuming a high-fat diet IN GENERAL.
And along with decreasing the formation of bodyfat, which the MCT's also do, they increase the amount of existing bodyfat broken down and greatly decrease bodyfat levels. MCT's actually work against the diet in terms of muscle production and fat breakdown".
This is just flat-out false. Unless there's some other component to his argument that you didn't copy here, this conclusion about MCTs working against muscle production is nonsensical.
Basically, the only way MCTs will work against you is by consuming too much of it at once while eating very little else. But you'd have to really be TRYING to make that happen, e.g. putting 3Tbsp of coconut oil in your coffee. And even then, the effects can be useful -- you can USE those ketones for hard exercise and avoid the insulin spike.
Kiefer is hardly recommending that anyone eat a shake-based diet where MCTs or coconut oil is the only fat source. He recommends that people eat Real Food and use MCTs / coconut oil as a tool. Long-chain triglycerides as well as monounsaturated fats and a few poly-unsaturateds still make up the vast majority of fats consumed on an ultra-low-carb diet composed of Real Food.
So the idea that MCTs should be avoided is silly, and the idea that there are people recommending the consumption of vast amounts of them is probably a straw man.