Ever since I switched some foods for the lower calorie versions like white bread to wheat, lower cal jellies, Peanut butter, etc I find that I am getting sick to my stomach much more often. Happen to anyone else?

Have you changed anything else? Sorry, I don't know your story. Have you cut calories considerably to lose weight? If you have cut back substantially on starches/sugar you could be suffering from a yeast die-off reaction...which is a good thing if you had a yeast overgrowth in your gut lining...just a thought. Or it could be the flu bug. Can you pin-point it to a specific food?

Well it may be that you are switching to more "non-natural" things.

I have no idea what exactly you switched to but for example:

Regular maple syrup is loaded with calories but it made with sugar, which is more "natural" than sugar-free sugar that has very little calories but sweetened with chemicals similar to Splenda. I thought of this sugar example when you said "low calorie jams" which may be cutting out the sugar to lower the calories, but adding in chemicals to keep the sweetness.

Personally, when I eat foods with artificial sweeteners or artificial ingredients, my stomach does not like them!

So take a look at the food labels of the foods that are new in your diet. Look for words you can't read or anything that it not "natural." That would be my best guess because that is what bothers me.

Remember that the more whole and fresh foods you can eat, the better! I definitely think it is more important to eat good things under your calorie limit, rather than eating a bunch of processed "low calorie" foods under your calorie limit.

If you are using a lot of sugar free foods, the artificial sweetener that is added to replace the sugar can cause stomach upset and diarrhea if you eat too much of it or sometimes people just cant tolerate it.

Thanks everyone. I am going to take a look at the labels but I'm thinking that it might be the artificial sweetners causing it. I never really thought about it being a problem until you guys mentioned it. Thanks!

the first week I did low cal I felt sick to my stomach and felt kinda dizzy at times.. I almost felt lie kI was going through sugar withdraws.. because I also felt mild anxiety at times.. it was kinda odd.. I think my body was so used to eating junk that when I fed it healthy it was kinda in a shock... BUT now it thanks me! because when I eat the bad foods I used to I fell sick now and it never tastes as good as I remembered!

I finally kicked artificial sweeteners last year after an incident when I was in Germany: I'd eaten a few, ok a whole small tin, of boiled sweets which were sweetened with one of the -itol sweeteners. They were good.
The next day I did the 40 minute tram trip into church, where I was leading a service, then set off for the train station to make a several-hour journey into the countryside for a few days' break.
About 10 minutes' walk away from the church, things felt um shifty.
I headed for the central public conveniences. I saw men going in and out. hurrah! Nope, the ladies' was closed. Locked. kaputt.
I mis-read the Sunday timetable, and got a tram going in the wrong direction.
I got off and stood for half an hour waiting for the right one.
Got to the station.
Sprinted (sprint? moi?) for the facilities, abandoned my suitcase in the basin area outside, no longer caring whether anyone stole it or not, not that they would in Germany but I didn't care.
Relief.
but I have never knowingly eaten -itols again!!!!! Lesson well learned/gut gelernt!

I also find artificial sweeteners can cause upset tummy. I can use a little but have to watch out. Also things like weight loss shakes and other diet foods cause me that nauseous feeling. I try to stick to whole foods so I don't wind up feeling green.

I think that I have it figured out. I "tested" myself with different foods and drinks I believe that it is the diet drinks. I would have at least 1 a day so I skipped a day and drank nothing but water the next day tried a diet drink and spent a good amount of time after feeling sick. No more diet drinks for me!