People think that because diet soda doesn't affect your blood sugar in the present moment, that it obviously doesn't lead to weight gain, in fact maybe it helps you to lose weight. Well that may be true in the short term, in the long run, we know from studies that it is anything but true people who drink diet soda in the long run are more prone to obesity, depression, heart disease so we actually know that sort of what is logic common sense is actually the opposite of what is true in the real world why that is is because, it does a few things that are really problematic, it is the re-calibrating of the taste buds it is not so much what you are doing in the present moment but it is that diet soda drink that or tend to eat sweeter foods all day long.
The other theory is that it may be wrecking your metabolisms. So what happens in the brain when it perceives sweetness, your brain knows eat a sugary food like an orange, blood sugar needs to release hormones to wrap up your metabolism to burn that off. Well, in the short term an artificial sweetener is great because you're getting sparks your body wraps up metabolism and you don't loose any weight, but then after a while the brain is a very smart thing like any other learning process, in the brain like for example tolerance, when it comes to alcohol, he's right.
It starts to adjust on what it knows to be true over the long run. So then you're having a diet soda, you're having an artificial sweetener and what happens is your brain starts to know, oh, I don't need to rev up the hormones to rev up the metabolism, and then what happens when you do eat that cupcake your metabolism doesn't rev up as much as somebody who doesn't drink diet soda or artificial sweeteners does and will therefore gain weight in the long run.