Why You Should Keep Your Finger on the ‘Pulse’ of Carb Substitutes

By Michael Lim

4 September 2019

Two types of lentils, red to the left and brown to the right

We’re all familiar with healthy ‘superfoods’ you can find in nearly every grocery store, ranging from blueberries (famous for their anti-cancer antioxidants) to broccoli (high in nutrients such as vitamin C). Now, new research from Prof. Alison Duncan from the Department of Human Health and Nutritional Sciences suggests adding another member to that esteemed list of foods: lentils.

Lentils are a type of pulse. Unlike the pulse you’re most likely thinking of, lentils are part of a group of edible seeds from the legume family. Other notable pulses include chickpeas, dried beans, and dried peas. Lentils are a fantastic source of protein and cause only slight increases in blood glucose levels following consumption, making them ideal for diabetics. Lentils are also packed with nutrients and are especially high in dietary fibre. Higher intake of dietary fibre may increase feelings of satiety, in turn reducing overeating, obesity, and the disease risks associated with obesity.

Despite their exciting potential health benefits, however, there is surprisingly little research on lentils.

“There is a need for evidence-based information to advance the inclusion of pulses in dietary recommendations,” says Duncan. “Studying satiety is a relevant means to examine food intake and obesity risk, and can also translate into a quick and feasible rationale for people to consider including pulses such as lentils into their diet.”

Instead of testing lentils in a head-to-head taste test against other commonly eaten carbohydrates, Duncan took a different approach. Alongside Dan Ramdath from Agriculture and Agri-Food Canada, recent graduate student Sandra Clark, and a team of graduate and undergraduate student researchers, Duncan took aim at the ingredients in two commonly consumed foods: muffins and chilies. By replacing wheat in muffins and rice in chili with either red or green lentils, Duncan and her team could study the effects of lentils on satiety in vastly different foods via a minor substitution. Such substitutions may better reflect real life, where providing a comparable replacement can make dropping a particular food item much easier for resistant individuals.

The researchers surveyed 24 healthy young men and women on how palatable (e.g., taste, texture) they found the lentil and regular muffins and chilies, and how the muffins and chilies affected their satiety (e.g., fullness, desire to eat).

Interestingly, green lentil muffins were perceived as generally less palatable than both red lentil and wheat muffins, and there was no effect on satiety. On the other hand, when it came to chili, both green and red lentil chilis were generally perceived as more palatable than rice chili. However, only green lentil chili led to a significant increase in the feeling of satiety. In other words, green lentil chili was not only more delicious, but it also reduced the desire to eat!

Now, before you start replacing all your carbs with lentils, Duncan and her team warn that the amount of food consumed did not differ between the different substitutions even though the study participants felt fuller after eating green lentil chili. The reason for this is not immediately clear, as satiety and food intake are complex responses that can be extremely difficult to unravel. For example, a person may dislike a food, but if they are told the potential health benefits it may provide, it can promote consumption.

To better understand how pulses can help reduce risk of chronic diseases like obesity, the Duncan lab is continuing its investigations, including looking at the effects of lentils and other pulses in older individuals, and how they impact health indicators such as cholesterol levels. For now, Duncan advises people to keep their eyes open for future research, and to educate themselves on the benefits of pulses.

With Canada the leading producer of lentils globally, one thing is certain: we have a large amount of this healthy alternative right here in our backyard.

“We are so lucky to have such a rich source of nutrients in lentils at our fingertips here in Canada, with great potential to assist with body weight management through satiety,” says Clark. “By continuing to research these ‘ingredient swap’ approaches, we can provide enjoyable ways to consume lentils and ultimately increase the health of Canadians while supporting Canadian agriculture.”


Funding for this research was provided by the Growing Forward 2 Pulse Science Research Cluster with funding from Agriculture and Agri-Food Canada and Saskatchewan Pulse Growers.  


Read the full article in the Journal of Nutrition.

Read about other CBS Research Highlights.