Maybe he was doing one of those "try a ketogenic diets for 30 days", or stumbled upon one of those keto advocates who only eats meat and lard. If all you read

Maybe he was doing one of those "try a ketogenic diets for 30 days", or stumbled upon one of those keto advocates who only eats meat and lard. If all you read about low-carb diets is the first paragraph about any popular news story about them, then what you know is that low-carb diets are the ones where you can eat lots of meat and you should shun any foods with sugar or starches.