Pulses are a group of plants that are cultivated exclusively as dry grains and not for extraction of oil as in case of other plants that have pods such as peanuts.
Pulses are also called pulse grains or grain legumes. Most commonly consumed pulses are chickpeas, lentils, kidney beans, pinto beans, navy beans etc.
Pulses are a rich source of dietary fiber.
They are a good source of digestible protein and carbohydrates Pulses are low in energy density.
These and another few components present in pulses are responsible for the energy regulating property of pulses which helps in weight loss.
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Weight loss - a few important things
Multiple factors are involved in regulating appetite and energy balance, few of which are discussed below:
Satiety: Satiety is the feeling of fullness after a meal. Consumption of pulses supports a slower return of hunger and facilitate lower energy intake. Proteins, dietary fibre and certain carbohydrates present in pulses stimulate satiety.
Glycemic response: Glycemic response is the effect of consumption of a certain food on one’s blood sugar.
Slow gastric emptying: Gastric emptying is the process by which food leaves the stomach. The dietary fibre present in pulses is digested very slowly.
Also, certain starches constituting pulses are resistant to digestive enzymes. These together slow down the digestive process and reduce appetite.
Digestive enzyme inhibitors: Pulses contain certain compounds which prevent the digestive enzymes in our body to breakdown proteins and carbohydrates. This plays an important role in weight regulation.
Energy density: Since pulses are low in energy density, they contribute to satiety and limit further energy intake.
After understanding the above concepts, let's find out what science says about pulses and weight loss.
Pulses for Weight Loss
Following research studies demonstrate various dietary patterns and interventions by which pulses have been tested for weight loss.
1. Pulses as a source of Dietary fibre
Pulses contain approximately 15-32% dietary fibre. Of this 33-75% is insoluble fibre and rest is soluble fibre.
Insoluble fibre has a laxative effect- it allows food to pass through the digestive system which helps reduce absorption of fats and cholesterol.
Soluble fibre, on the other hand, helps to maintain healthy blood cholesterol levels and helps the body derive energy from fat.
Overall consumption of fibre helps reduce fat uptake and also aids in burning fat.
A research study investigated the nutritional effect of two high fibre low-calorie diets on overweight and obese individuals.
Subjects were asked to consume either of the two 1400 calorie diet which contained 25-35g fibre from beans or from fruits, vegetables, and grains.
It was observed that both the diets resulted in almost the same outcome. Calorie intake was reduced from around 1600 kcal/day to 1300kcal/day.
Mean weight loss was about 1.4 kg. Participants reported an increase in fullness and reduced appetites.
The National Health and Nutrition Examination Survey conducted in Canada assessed the trend of nutrient intake and other parameters in bean consumers.
Compared to non-consumers, bean consumers were found to have lower body weight and small waist size.
Bean consumers had a higher intake of dietary fibre and minerals.
Also, baked bean consumption was associated with good blood pressure levels.
Bean consumers were had 23% reduced the risk of increased waist size and 22% reduced risk of being obese.
Whole grain intake is said to help in weight loss. A clinical trial compared the effect of consuming a diet rich in pulses and whole grains to a control diet on weight loss and nutrient intake.
Dietary fibre and nutrient intake increased in the intervention group.
Mean weight loss, however, was not different in either group. (around 6 kg) Waist circumference decreased in the intervention group compared to control.
An experimental trial was conducted to determine the effectiveness of legume consumption on weight loss. In the trial, participants were asked to reduce energy intake by 30% and they were randomly assigned to the following groups:
- Group 1: 3 cups of legumes per week
- Group 2: Women – 1.8 cups of legume per day ,Men- 2.7 cups of legume per day ; 6 days per week
- Group 3: control diet
Weight loss was greater in the group 1 and 2 rather than the control group.
At the end of 6 weeks, weight loss in group 1 was around 3.4 kg, group 2 was around 3.9 kg and in control group, the loss was of 1 kg.
What does this mean? Since pulses are a good source of dietary fibre they aid in weight loss. They bring similar weight loss outcomes as whole grain. Consuming of at least 0.5 cups of legume per day can help in weight loss.
2. Pulses as a source of digestive enzyme inhibitor
Carbohydrates are a rich source of calories. Carbohydrates are broken down into simple units called monosaccharides, before being absorbed in the body.
This activity is brought about by two enzymes- amylase and glucosidase.
White beans are a source of compounds that prevent these enzymes from breaking down carbohydrates, thereby reducing their absorption and promoting weight loss
A product named Phase 2 Carb controller has been developed from white bean extract which inhibits the activity of enzymes that breakdown carbohydrate.
In the clinical trial, obese individuals were given 1500 mg Phase 2 twice daily with meals for 8 weeks.
The Phase 2 group lost on an average of 3.79 pounds compared with the control group that lost only 1.65 pounds.
What it means? Digestive enzyme inhibitors in pulses can help in weight loss.
3. Pulses as a source of Protein
Dietary protein helps in weight loss and maintenance by inducing satiety and increased energy expenditure upon digestion. Also, proteins positively influence bone health.
Legumes are a rich source of protein. A study was designed to assess the effect of four hypocaloric diets rich in protein on weight loss. The diets were as follows: Control diet, Legume diet, Fatty fish diet, and high protein diet.
Maximum weight loss was achieved by high protein diet and legume diet and cholesterol levels were reduced in all groups except for fatty fish.
What it means? Incorporating high protein content such as legumes in a hypocaloric diet can facilitate breakdown of fats at cellular level leading to weight loss.
4. Pulses to improve satiety
Slow return of hunger and satisfaction after consuming a meal is affected by a number of parameters such as the volume of food, circulating hormones, the frequency of meals etc.
Pulses are rich in fibre, protein, and carbohydrates which help promote post-meal satiety and reduce further meal intake.
A diet rich in chickpeas is reported to increase satiety and alter food habits. Participants were asked to consume a regular diet for 4 weeks followed by chickpea supplemented diet (104g/day) for 12 weeks and then regular diet for another 4 weeks.
Food intake was lowered during chickpea supplementation. Satiety increased with chickpea consumption and also bowel functioning was improved.
Pulses are not really anybody’s favorite food item.
Perhaps one can look forward to incorporating it in a different manner in their diet.
A study was conducted to evaluate the palatability, satiety and glucose response to consuming chickpea flour bread.
The chickpea bread had acceptable palatability but no change in glycemic response or satiety was observed.
What does this mean? Results indicate that chickpea consumption can aid in weight loss by promoting satiety. However chickpea consumption in any other form may not help in weight loss.
Other Health benefits of Pulses
Though its likely that pulses don’t make it to your top favorite food list, they should. They are packed with loads of other health benefits too:
- They are rich in protein, fibre and carbohydrates.
- Consuming half a cup of beans per day can supplement you with a number of vital nutrients.
- Pulses possess anti-cancer activity.
- Phytochemicals (compounds present in plants which give them unique properties) present in pulses serve as strong antioxidants.
- Consuming pulses can improve cholesterol levels and other parameters that increase risk of cardiovascular disease.
- Pulses are good for people suffering from diabetes as it helps to maintain a balanced glucose and insulin levels.
- Beneficial effects of pulses on chronic diseases are being investigated.
Pulses should be consumed in moderate amounts. They are reported to cause mild discomfort such as gas and bloating.
No significant adverse effects of pulse consumption have been reported.
Based on the scientific evidence, we can safely conclude that pulses indeed help in weight loss.
This is primarily due to the rich nutrient composition of pulses that aids in promoting satiety and influencing appetite.