09/26/2014 04:10 pm ET Updated Nov 26, 2014

5 Health Foods That Can Tax Your Digestive System

I know what you're thinking. Please, not another list of things I can't eat! No, that's not what this post is all about. Think of it more as a troubleshooting session -- finding hidden culprits that could be behind some of your digestive woes and exploring how to make these foods easier to digest (or moderate).

1. Nuts
These crunchy and convenient bites of protein contain a pesky little thing called phytic acid (phosphorus in its storage form). Phytic acid is indigestible and can block minerals in our food from being absorbed, notably zinc and iron. This causes some people to feel heavy and uncomfortable after eating nuts, which is a shame since they are otherwise a great source of protein, healthy fats, fiber and minerals.

But good news! Soaking nuts can reduce the phytic acid content and make them much easier to digest.

Soaking Nuts
-- Give raw nuts a 12-hour soak in warm, salted water.
-- Then dehydrate them at 150 degrees (or as low as you can set your oven), shuffling them in the pan occasionally. The duration depends on the temperature and the nut, but you can expect seven to 12 hours.
-- This is a good thing to do when you're planning to be at home for most of the day (don't leave the oven on if you leave).
-- You can soak raw sunflower seeds the same way. They dehydrate much more quickly.

If you have a condition called diverticulitis, you may be avoiding nuts (and seeds) to avoid flares. If you've noticed a definite connection, steer clear. But new research shows that nuts and seeds may not necessarily cause flares and can be part of a balanced diet for those with this condition. Listen to your body and talk with your doctor!

2. Coconut and Almond Flours
Grain-free treats using coconut and almond flours are a boon for those who like baked goods, but don't tolerate grains well -- pancakes, muffins, or even a flour coating for chicken or fish. Even if you aren't looking to go grain-free, these ingredients can pack a lot of protein into your family's snacks while cutting out the gluten.

But some people can't tolerate even small amounts of these flours. And since they are modified/concentrated foods, it's wise to use moderation.

Coconut flour is made by grinding the pulp byproduct from the coconut milk extraction process. Stripped of its fat content, it packs a heavy dose of fiber which can be difficult for some people to digest.

Almond flour is simply ground-up blanched almonds. But the quantity can be deceiving. It's remarkably easy to eat a small mountain of almonds when sitting down to a mini-stack of almond-based pancakes!

Enjoy these flours if you love to use them in baking, just don't load up on them every day!

3. Red Meat
Red meat is a fantastic source of protein, iron, zinc, selenium, niacin, B6 and B12. However, it can cause indigestion and constipation if you are low in stomach acid and digestive enzymes -- and many people are.

I do value the nutritional benefits of red meat and include it as an option in my new book, but I only introduce it after a time of correcting the gut pH level, increasing digestive juices and stimulating gut motility. I'll be sharing some great tips on how to do this in an upcoming post!

If you digest red meat well, eat it in moderation and don't forget that there are many sources other than beef. Goat, bison and lamb are all great choices, often higher in nutrients.

4. Citrus Fruits
While citrus fruits don't cause gastroesophageal reflux disease (GERD), they can irritate an already inflamed esophagus. In short, heal your GERD before indulging in citrus!

On the flip side, if the esophagus is in good shape, drinking lemon water in the morning can have a healthy cleansing and alkalinizing effect on the body, in time improving digestion.

5. Raw Cruciferous Vegetables
Eating cruciferous vegetables (such as broccoli, cabbage and kale) reduces your risk of cancers of the digestive tract. This protective effect is attributed to the phytochemicals and high fiber content in the plants. But this fiber, cellulose, is also what makes these vegetables harder to digest in their raw form.

Glucosinolates (sulphur-rich phytochemicals found in cruciferous veggies) have an anti-tumor effect, but only when they are converted to isothiocyanates (ITC). In the past it was thought that cruciferous veggies had to be eaten raw for this to take place, since the glucosinolate-ITC conversion process requires the enzyme myrosinase which is destroyed during cooking.

But a fascinating study by The Fred Hutchinson Cancer Research Center has shown that although myrosinase is destroyed at high temps, cooked cruciferous vegetables stimulate the production of myrosinase-like gut bacteria that convert glucosinolates into ITC.

This is great news for people seeking the cancer-fighting benefits of cruciferous vegetables but can't tolerate eating them raw! You can also try fermenting your vegetables -- this breaks down the cellulose while preserving the enzymes.

I hope this clears some things up for you! If you have any questions, go ahead and ask in the comments section!