About two weeks ago, before I got sidelined by a cold, I came across this news in a few of the newsletters I subscribe to: Bring on the beans for diet health?
I wasn't surprised to see these results, since the people who ate legumes on a daily basis would up eating overall more fiber (thereby slowing down the emptying of the stomach and thereby slowing down the impact of the carbohydrate on the blood glucose levels); and beans, because of their lower net carbohydrate content per cup compared to some other carbohydrates like pasta or rice. In other words if you have a cup of say, lentils, you would consume only about 24 grams of net carbohydrate and if you consumed a cup of pasta you would have consumed 33+ grams of net carbohydrate (and it comes out roughly the same if you eat "whole wheat" pasta), so chances are people who were getting their carbs from legumes had a better chance of eating less carbohydrate overall.
But there's the rub; you would have had to consume legumes INSTEAD OF SOMETHING ELSE to get the benefit. Which is why I always wince whenever I see an article encouraging people to "add" something to their diet. Rarely do I see the flip side mentioned; that in order to keep your calories and carbohydrates under control you also have to (most likely) give something up. So if you do include legumes more often for whatever reason, you will have to sit down and figure out what else in your meals have to go--and usually it's other foods that fit in the carbohydrate category. If you choose to stir some beans in the chili, you better be careful with the amount of cornbread you're eating with it. If you are making a lentil stew, be careful with how much rice you have (and some people just forgo that all together). And remember that this is true of pretty much any other food with caloric value that you are trying to "add" to your diet. (The exception would be green leafy vegetables as their caloric density is pretty low, which is why it helps to add vegetables to a meal to make it look bigger and more satisfying to the eyes!)
The other reason that this article jumped out at me is that as a person with Irritable Bowel Syndrome, legumes happen to be on my personal "do not eat list" because beans contain galacto-oligosaccharides and are poorly absorbed by people like me; so if I added beans in that amount I would get to deal with serious abdominal pain for the next two days.* I eat a variety of other protein and fiber sources, so I know I'm not going to be deficient if I don't eat beans (sure do miss that hummus though!). Which brings me to another point, usually whenever I see an article like this published the comment section is full of people screaming "You want me to eat beans so I can die!" or something like that. No, most of the time the people who publish these studies are perfectly aware that these results may not apply to everybody; the media source reporting on that does not always convey it, but when people do research they often are looking at only one subset of a population.
So if you see an article advocating that you add something to your diet, here's how to do it skeptically and safely.
1) Ask yourself if you are already eating other foods that give you that particular nutrient. Maybe your intake is already just fine. Doesn't mean you can't try something new, but there won't be anything "magical" about whatever that new food is.
2) Ask yourself if there is anything in that particular food that would cause problems for your health (like me and the legumes) or hinder you meeting your health goals. For example, if you've heard that adding a square of dark chocolate a day might be good for you, but you have trouble eating just one square, then it may not be a good idea.
3) As stated above, think about what else you would have to eat less of so that you can substitute that food and still meet your nutritional goals.
Take home message--you have to add and subtract to stay in balance.
*I know what kind of advice you are all going to give me to help ease the GI distress that comes with eating beans. Trust me, I have tried it and it's not right for me. Thanks for trying to help though.