Sweeteners vs. sugar.
Most if not all artificial sweeteners will mess up your blood sugar balance.
You get a sweet taste on the tongue when you eat sugar. That sweet taste is a signal to the liver: "there'll be lots of blood sugar from the digestive tract in a minute or two, can't have too much blood sugar at once, I'll pull the blood sugar right now."
And that's fine and dandy as long as that sweet taste really is a high-caloric fast-showing sugar. For instance candies, sweet pastries, honey, or the "health foods" grape, grape juice, or carrot juice. And similar things.
But if you've just eaten an artificial sweetener (for instance aspartame), your liver is fooled into pulling the blood sugar, but you don't get the corresponding blood sugar surge from the food you just ate.
So you suddenly have low blood sugar, and all that comes with that: tiredness, irritation, and/or the Munchies with a capital M. You have low blood sugar, you need something sugary now.
So you add sweeteners to your coffee and munch on candies, all the time. And you wonder why you simply can't lose weight ...
... I've seen this, really bad, in a client. She was doing the sweetener - sweets - sweetener - sweets blood sugar yo-yo, and she was munching on candies throughout our interview. She didn't notice it herself.
Part of the problems she saw me for were related to the load of blood sugar, so I explained to her that sugar is not a necessary part of our diet, and to ditch the candies. "Right,", she said, "I'll get my sugar from honey then." No, sugar is not a necessary part of our diet, you shouldn't switch to honey either. "So can I just eat sugar then?" No, sugar is not a necessary part of our diet.
We all react to the low blood sugar which artificial sweeteners bring with them, but it's rare to see it that clearly.
I gave liver herbs, told her to ditch both the artificial sweeteners and the sweets, and told her to do magnesium, chromium, zinc, B6, and fish oils, in order to get the insulin - blood sugar system working properly.
Stevia or licorice won't fool the liver into pulling the blood sugar, but their taste isn't just sweet.
The moral of the story: use sugar or honey if you have to sweeten your coffee. And enjoy that sweet coffee: sip it slowly, don't gulp it down.
I'd also suggest ditching the "cholesterol is bad for you" idea, and eating full-fat foods: most low-fat foods are loaded with sugar.