The diet is rich in L-carnitine and promotes weight loss, as some elements suppress appetite in addition to moderate calorie intake. L-carnitine + coffee is also good.
Coffee and lemons have a wide range of health benefits, mainly due to their antioxidant content.
However, there is no evidence to support the claim that drinking coffee with lemon relieves diarrhea or causes fat to melt.
As for the rest of the claimed benefits of the mixture, they can be obtained by drinking coffee or lemon juice separately. This way, there is no need to mix the two if you don't like it.