annabella. Most of those foods (sweets and LC desserts) contain sugar alcohols in fairly large amounts. I looked at one bar today that had 23g of sugar alcohols. That's a lot.

These have an unfortunate side effect in a lot of people, me included.They can cause abdominal cramps, bloating and/or diarrhea.

Feeling lethargic and nasty the next day could be because you're sensitive to the sugar alcohols. The reason they are subtracted from the total carb count is because they "don't affect the blood sugar levels". But many disagree with this and feel that they are sensitive enough that the sugar alcohols do in fact cause a rise in BS. That might be why you feel lethargic and nasty.....you might have had more carbs for the day than you realized.

There's nothing wrong with LC desserts and meal replacement bars as long as you don't over do them. A treat once in a while, fine....but it's probably not a good idea to eat foods with sugar alcohols on a regular basis.