Of the three macronutrients – protein, carbohydrates, and fat – protein is the most satiating. When you eat a meal high in protein, you stay fuller longer than when you eat carbohydrates or fat. Yet, you find protein in both plant and animal foods. Does one have an advantage over the other in terms of suppressing appetite? A new study carried out by researchers in Denmark took a closer look at this issue.
Plant vs. Animal Protein: What the Study Showed
In the study, researchers asked 43 healthy men to eat one of three breakfasts. Each participant devoured each breakfast at different times. The meals were similar in calorie content, although each differed in the type of protein it contained. The first breakfast consisted of a patty of meat and mashed potatoes. The second was a patty made of beans and lentils along with mashed split peas. The third was a low-protein legume patty with a combo mash of split peas and mashed potatoes. All patties were prepared with canola oil, spices, and butter.
The results? The participants felt significantly fuller at their next meal after eating the high-protein, plant-based patty and ate 13% fewer calories. In this case, 13% fewer calories was equivalent to about 100 calories. That amount of calorie deficit could add up to significant weight loss over time. What’s interesting is the participants also felt less hungry after eating the low-protein vegetable patty as well, more so than after eating the high-protein meat based patty. How can you explain this?
The researchers believe the difference is the fiber content of the plant-based patties. As you know, fiber comes only from plant-based foods and beans and lentils are quite high in fiber. The high-protein plant patty in the study had 25 grams of fiber versus only 6 grams of fiber in the meat patty. The fiber in the meat patty contained fiber from the potatoes used as a filler. The two patties had similar amounts of protein.
What’s so magical about fiber and appetite? Fiber slows down how quickly food moves through your digestive tract. Since fiber isn’t broken down or digested, it reaches your intestines intact. Once there, friendly gut bacteria can feast on the fiber, giving them the nourishment they need to thrive and keep your gut healthy. These bacteria also play a role in the immune response and inflammation. Some studies show that diets high in fiber reduce markers of inflammation. That’s important since inflammation is linked with a variety of diseases and likely plays a role in obesity as well.
Viscous Fiber is Best
Based on some studies, not all fiber equally reduces food intake later on. The best form of fiber for suppressing appetite and calorie consumption is viscous fiber. As the name implies, viscous fiber is fiber that easily absorbs water and forms a thick, gelatin-like mass. Viscous fiber is found in various components in the cell walls of plants. Some of you may be familiar with are beta-glucan, a viscous fiber in oatmeal and pectin, a fiber abundant in apples. It’s no coincidence that these foods are some of the most satiating. However, if oatmeal and apples aren’t your thing, a number of fruits, vegetables, legumes, and whole grains contain varying amounts of viscous fiber.
Viscous fiber has other benefits as well. It’s viscous fiber that’s most effective for lowering cholesterol, which bodes well for heart health. Plus, this form of fiber slows the rise in blood sugar you get after a meal, making it ideal for diabetics and pre-diabetics. Another type of fiber, non-viscous or insoluble fiber, is also a component of many fruits and vegetables.
Another Reason to Get Enough Fiber
If feeling full, keeping your gut health, and lowering your blood sugar and cholesterol isn’t enough, there’s another reason to get more fiber. A meta-analysis published in 2014 showed that for every 10 additional grams of fiber an individual ate, it lowered their risk of dying by 10%. Unfortunately, the average person gets less than half the recommended amount of fiber daily. Women should get 25 grams of fiber per day and men 38 grams.
Sadly, most people barely get half that amount of fiber. That’s because the average person gets a substantial percentage of calories from processed foods where the fiber has been removed. Some packaged products add synthetic fiber but it’s not clear whether the synthetic version has the same health benefits. Your best bet is still plant-based foods, including fruits, vegetables, whole grains, nuts, and seeds. By eating a variety of plant foods, you get more than one type of fiber as well as a diversity of phytochemicals linked with health.
Plant Protein Rocks
As you can see, plant protein offers an advantage that animal-based protein doesn’t. For one, it contains fiber. As this recent study shows, fiber has a similar impact on appetite as protein and when you combine the two into one food, you get a super-satiating combo. Plus, you get the other health benefits that fiber offers.
Which plant-based foods are highest in fiber? At the top of the veggie charts is the humble artichoke with 10 grams of fiber per serving. Artichokes are a good source of antioxidants as well. When you eat vegetables, like artichokes with whole grains or legumes, you get a substantial source of protein as well as additional fiber. Because most plants are not a complete source of protein, it’s important to eat a variety of plant-based foods.
Word of Warning
After realizing the appetite-suppressing, health benefits of plant foods and fiber, you might be tempted to load up on it. Not so fast! Your digestive tract needs time to adjust to a higher fiber diet. Slowly introduce more fiber so you can avoid the gas and bloating a rapid increase in fiber can trigger. So, slow down the pace with which you add fiber to your diet but make sure you’re gradually adding more plant protein to your diet.
References:
LiveScience.com. “Fighting Hunger? Plant Protein May Keep You Feeling Full Longer than Meat”
J Clin Invest. 2012 Jan 3; 122(1): 153–162.
J Nutr. 2008 Mar;138(3):439-42.
Authority Nutrition. “Good Fiber, Bad Fiber – How The Different Types Affect You”
Today’s Dietitian. Vol. 17 No. 8 P. 34. August 2015.
Am J Epidemiol. 2015;181(2):83-91.
Arch Intern Med. 2012;172(21):1653-1660.
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