You probably read the title of this article or the one-sentence descriptor and got just a little bit excited. Damn straight. Everybody wants “zero-effort” fat loss.
I’m a little worried, though, that I’ll reveal the name of this special weight-loss food and your gut reaction will be that I cat-fished you. It might remind you of the time Mom put a Tootsie Pop in your lunch, only to find that she’d removed the candy head, replaced it with a small sprig of broccoli, and then wrapped it back up in the original Tootsie Pop wrapper.
But bear with me for a minute. The food I’m talking about really is something to get excited about, even though its very name and reputation screams ordinary and dull. The food is Phaseolus vulgaris, a.k.a. the common bean.
The reason I’m so pro-bean lately has largely to do with a recent study of 246 subjects that found that just adding some beans to the diet on a regular basis was related to less body fat and smaller waists than low bean intake.
And while the study only involved women, it excluded men for practical reasons (they would have had to double the number of subjects to maintain the same statistical power). As such, the big-picture results would probably apply to men, too.
6 Reasons Why Eating Beans Resulted in Fat Loss
Before I get into the particulars of the study, let’s first look at why eating beans regularly or semi-regularly was associated with better bodies. The authors of the study thought there were at least six contributing factors:
- According to US dietary guidelines, beans are the only food that gets dual classifications as both a vegetable food and a protein food, and protein is the most filling of the three macronutrients (so bean eaters typically end up eating less of other foods).
- While beans are a nutrient-dense food, they’re not a calorie-dense food.
- Beans are among the lowest glycemic-index foods. Compared to other foods, beans cause less of a rise in blood sugar levels.
- Beans contain a lot of dietary fiber, with one cup containing approximately 10.4 to 15.6 grams. Fiber, particularly soluble fiber, binds up fats and sugars, leading to reduced absorption in the digestive tract.
- One study (Reverri et al.) found that black beans, at least, increase cholecystokinin and peptide tyrosine tyrosine (PYY), which are satiety-increasing hormones. Again, the more satiated you feel, the less you’re inclined to calorie-up on other foods.
- Beans have a favorable impact on the intestinal microbiota and a healthy gut has been found to play a part in body weight and adiposity.
In short, “beans possess a unique combination of dietary qualities.”
Lots of Results, Little Effort
The study involved 246 women recruited from more than 20 cities in the Mountain West. Each participant was asked to fill out the lengthy “Block Food Frequency Questionnaire,” which is considered by dietary experts as a legit and reliable instrument for assessing dietary intake.
The questionnaire is eight pages long and even contains four specific questions about types of beans and legumes ingested: (1) refried beans or bean burritos; (2) chili with beans; (3) baked beans, pintos, or other dried beans; and (4) bean, split pea, or lentil soup.
Participants were asked to indicate how much and how often they ate those items and the results were used to calculate total annual consumption.
When they compiled all the stats and compared the top third of bean eaters with the bottom third of bean eaters, they found a mean body fat difference of almost 4 percentage points and an average waist size difference of almost 4 centimeters (one and a half inches).
You should also know that the researchers took physical activity into consideration, too, as each participant was required to wear an “accelerometer” on their hip to measure how much they moved. Those results, along with age and education, were considered “covariates” and were included in their analysis of the results.
What Kinds of Beans and How Often?
Phaseolus vulgaris, aka the common bean, includes a whole lot of different varieties of bean, including kidney beans, snap beans, pea beans, wax beans, Northern beans, haricot (navy) beans, field beans, and black beans.
All of them should pretty much have the same beneficial dietary attributes, so feel free to avoid any that taste yucky to you.
As far as how many you should eat and how often, there’s no magic, precise number. The women in the described study were by no means consciously including beans in their diets to lose weight, but their yearly mean bean and legume intake was 50.4 cups, +/- 49.7.
Obviously, some ate a serious amount of beans while others apparently would not eat them in a box, not with a fox, nor in a house, or with a mouse.
You’d have to think, though, based on the results of this study and others, that including a small amount of beans (1/2 to 1 full cup) in 3 to 7 meals a week would make a noticeable difference in body composition over the course of months for nearly any man or woman, and that’s about as close to zero-effort fat loss as there is.
Make soup or chili with them, add them to salads, or do as I do and just use small amounts of canned varieties, seasoned with salt, pepper, and hot sauce, as side dishes.
- Larry A. Tucker, “Bean Consumption Accounts for Differences in Body Fat and Waist Circumference: A Cross-Sectional Study of 246 Women,” Journal of Nutrition and Metabolism, Volume 2020, Article ID 9140907.