That’s a complicated question, because yes there are weight loss drugs that mimic certain aspects of diabetes, but through different mechanisms of action. A good example is a SGLT2 inhibitor medication, which explicitly creates glycosuria in a non-diabetic person, which is kind of a defining feature of diabetes mellitus. While that’s a generally very effective drug and should be used more for obesity control, it will also increase incidence of UTI and (due to a loss of sugar and thus forcing metabolism of fats/proteins) ketoacidosis.

The insulin/glucagon relationship is why diabetic ketoacidosis only shows up in type 1 diabetics and not type 2 (they get what’s called hyperosmolar hyperglycemic state), and is an important part of liver fat production. Ketoacidosis is generally associated with that but is also present in starvation and alcoholics that don’t eat actual food.

The greater point I was making wasn’t about carbohydrates turning into fats. It’s that most fats and about half of proteins cannot be turned into carbohydrates. They must be metabolized into ketones and then acetone. If you absorb them and cannot store them like in the OP’s hypothetical, you’ll end up having to immediately metabolize them and will end up with ketoacidosis.