7 things you're eating daily that your body struggles to digest

• Milk is a common digestive irritant in people with lactose intolerance.
• Artificial sweeteners might save you a few calories, but they can also wreak havoc on your digestive system.
• There's a good reason that corn salsa you love to eat for dinner can show up later.

Keeping track of everything you eat and drink in a day might seem like a tedious task. But if you're trying to pinpoint foods that are causing digestive issues, it's a necessity.

Sure, some brightly colored snack foods are obvious culprits, but did you know there are other foods you're eating on a regular basis that your body struggles to digest?

1 Your body can't digest or absorb fiber.

Both insoluble (wheat bran, veggies, and whole grains) and soluble (oats, fruits, veggies, and beans) fiber are not digestible.

However, Chelsea Amengual, MS, RD, and manager of fitness programming and nutrition at Virtual Health Partners, told  that while we cannot digest fiber, and do not gain any energy from it, it is crucial to digestive health.

"Insoluble fiber provides bulk to our stool and food for our healthy gut bacteria, and soluble fiber helps slow down digestion and can even have a positive impact on heart health," she said.

2 Highly processed foods are hard to digest.

Greasy potato chips, candy, and even your favorite breakfast cereal contain ingredients your body struggles to digest.

That's because "overly processed packaged foods contain many additives to keep the products palatable and shelf-stable," explained Amengual.

"However, these chemicals (nitrates, fat-substitutes, and phosphoric acids) can be indigestible and potentially irritating to your gut lining," she added. Not to mention, they can wreak havoc on overall health over the long term.

3 Non-nutritive sweeteners aren't easy on the digestive system.

If your morning commute includes a trip through the drive-thru for a sugar-free latte, you might want to consider swapping out the artificial sweetener for the real stuff.

"Sugar-free sweeteners like aspartame do not provide calories and are not fully absorbed by the body," explained Amengual.

While the research is inconclusive on the safety of high doses, she said these sweeteners can be very beneficial to individuals with diabetes or other issues with blood sugar regulation.

4 Many dairy products are impossible for some people to digest.

That triple-chocolate milkshake with whipped cream you sucked down at dinner might be the cause of your bedtime stomach pains.

"Some people lack the enzyme to digest lactose, a natural sugar in dairy products," said Amengual.

However, even if you're lactose-intolerant, she said you might do OK with yogurts and aged cheeses. That's because the bacteria in these products feed off the sugars and do the digesting for you.

5 Seeds often go undigested.

There's a good explanation for why your stomach gets so angry after eating your favorite seeds.

"Raw seeds (sunflower, sesame, chia, etc.) often contain phytic acid, which can interfere with the absorption of minerals," registered dietitian Brynn McDowell told.

If you notice undigested seeds in your stools, McDowell said to consider soaking these seeds before eating to help remove some of the phytic acid.

6 The skin of bell peppers is hard to break down.

Bell peppers add vibrant color and sweet flavor to any chicken, beef, or veggie stir-fry. However, since the outer skin is very tough and fibrous, McDowell said it can be hard for the body to break down fully, especially if eaten raw.

"As a result, remnants can end up in the stool," she said. It can also cause stomach pain or gas for some people. But if you still want to enjoy peppers at meal time, McDowell said to remove the skin before eating.

7 Our bodies can't fully break down corn.

Remember being alarmed the first time you saw whole kernels of corn in your stool? If you eat corn on a regular basis, you might be familiar with this occurrence. McDowell said to think of corn like the tracker device of the body's digestive system - eat it for dinner, and you may notice some kernels in your stools later.

"This is because corn contains cellulose and we don't have the enzyme necessary to break it down fully during digestion," she explained.