A good friend of mine has celiac disease, which means she can't eat any foods that contain these "evil" ingredients: wheat, rye, barley, and possibly oats. If she does, she pays the price with painful stomach cramps, bloating, gas, and diarrhea, but the scary thing is that it can even be fatal. She's not alone; it's estimated that one in 133 people in America suffers from this disease.
Due to its prevalence, I'm sure you've noticed the shelves of gluten-free food options available out there from cereals, to baking mixes, to pizza dough, to pastas. I had my friend over for dinner the other night, and a mutual friend wondered if she'd be better off ditching gluten foods from her diet too, even though she has no problem digesting it. To find out if going gluten-free is healthier, read more.
Wheat, rye, barley, and oats are nutritious ingredients, so there's no reason a person who doesn't have celiac disease should give up foods made with them. I will say that often these ingredients are overprocessed and used in unhealthy foods. So while it wouldn't make sense to give up whole grain bread or whole wheat pasta, a person would be healthier if they passed up crackers and bagels made with enriched white flour. So you see, it's not the gluten that determines the nutritional value, it's how the foods are made. Also to be noted, I've seen plenty of gluten-free "junk food" such as brownies, cakes, and cookies that contain just as much sugar and fat (maybe even more to replace the gluten) as their gluten-filled counterparts. A person can eat a completely gluten-free diet that's high in saturated fat, cholesterol, sodium, and sugar, and end up being very unhealthy.
If a person goes gluten-free, and instead focuses on eating more fruits, veggies, lean proteins, and gluten-free whole grains such as quinoa and millet, then, yes, that diet is healthy. But it has nothing to do with the fact that it's gluten-free — it's just nutrient-rich. Ditching gluten from your diet is not a surefire path to health. It's best to choose foods that are the least processed and as close to nature as possible, regardless of whether they contain gluten or not.