My stomach used to be really sensitive about what it could and couldn’t handle (in terms of food) before a run or workout. Foods that are too dense or have too much fiber still make me feel sluggish and uncomfortable, but I can eat a variety of foods now.
As far as pre-run fueling, something with a lot of carbohydrates is a good choice. Depending on the length of a workout, 40-50g of carbohydrates is good, with a solid mix of simple sugars and more complex ones. Have something with electrolytes (sodium, potassium, magnesium) as well.
As far as nutrition and stomachability (yes, I invented that word) Clifbar is pretty spot on for me. Everybody’s different, but if you’re looking for a place to start, I would suggest Clifbars.
These are my favorite flavors! Black Cherry Almond is also a good one, but I didn’t have one on hand to snap a photo of.
For serious athletes, fueling up before and after a run is really important. If you run 7 miles or more in one trip, it’s a good idea to have some sort of snack before and after that balances the nutrients you will use and therefore will need to replenish. Even if you’re not training for a race and you’re just trying to lose weight, replenishing some of the lost carbohydrates and protein is essential for muscle recovery. After a 7 mile run, your legs will not feel so well the next day unless you give them the materials they need to repair themselves and grow.
I know a lot of women like Luna Bars but I can’t really vouch for them. I only ever tried one once (I think it was peanut butter flavored) and it tasted terrible to me. They would also be a good choice for a pre-run snack if you like the flavor but they are somewhat lacking in carbohydrates (20g-30g) so if you’re going on a long run (7m+) I would recommend have a few tablespoons of raisins as well. Smaller granola bars are fine for shorter runs (<7m).