Study suggests avocados suppress hunger, but can we trust the research?
Can avocados curb hunger?
The avocado is widely hailed as a superfood. With its creamy green flesh, it adorns dishes of all varieties and features in breakfasts, lunches, and dinners.
The fruit contains a rare combination of healthful fats and fiber and is associated with a host of health benefits.
A new study in the journal Nutrients now adds more evidence to consider, by showing that overweight or obese volunteers who had eaten avocado as part of a meal felt less hungry after 6 hours, compared with those who had eaten a low-fat, high-carbohydrate meal.
But there is a rub. This study received funding from the Hass Avocado Board (HAB) and is not the first of its kind with such backing.
But should this deter us from swapping carbohydrate for avocado?
Meals with avocados reduced hunger
Britt Burton-Freeman, Ph.D., an associate professor of food science and nutrition and director of the Center for Nutrition Research at the Illinois Institute of Technology, in Chicago, is the senior study author.
The team set out to test the effects of replacing carbohydrate with avocado in a meal on satiety, which is the feeling of fullness and reduction in appetite that we experience when we eat.
The study included 31 participants who were overweight or obese. The volunteers ate a breakfast meal consisting of a bagel sandwich, honeydew melon, oatmeal, and a lemonade-flavored drink on three separate occasions.
The control meal was low in fat and high in carbohydrate, while the two test meals contained either half or a whole avocado in the bagel sandwich. The overall calorie count was the same for each meal, but the breakfasts with avocado had triple the amount of fat and only two-thirds the amount of carbohydrate as the control meal.
The participants then recorded their subjective feelings of fullness, hunger, desire to eat, how much they wanted to eat, and how satisfied they felt after the meal at regular intervals for 6 hours. They also provided blood samples for analysis.
Volunteers felt more satisfied after meals containing either a whole or half avocado and said they felt less hungry after meals with a whole avocado.
Achieving satiety by different means
Blood analysis showed that different molecular messengers were responsible for satiety when comparing the meals with and without avocado.
While insulin mediated satiety after the low-fat, high-carbohydrate meal, there was a clear link between the gut hormone peptide YY and subjective satiety after the meal containing a whole avocado.
In the paper, the authors note that the research suggests “that how satiety is achieved through biological signaling may have important implications.”
When asked if the results came as a surprise, Burton-Freeman told Medical News Today, “Based on earlier work, I hypothesized that the fat-fiber combination of avocado would impart an enhanced satiety response.”
“The responses on the different satiety variables was surprising and helps us understand [or] think about how the fat and fiber may work to enhance satiety, even later, in the post-meal period,” she continued.
“For years, fats have been targeted as the main cause of obesity, and now carbohydrates have come under scrutiny for their role in appetite regulation and weight control.”
Britt Burton-Freeman, Ph.D.
“There is no ‘one size fits all’ solution when it comes to optimal meal composition for managing appetite,” she continues in a press release. “However, understanding the relationship between food chemistry and its physiological effects in different populations can reveal opportunities for addressing appetite control and reducing rates of obesity, putting us a step closer to personalized dietary recommendations.”
MNT asked Burton-Freeman if 31 study participants was a large enough number to draw conclusions from. She explained that the team had used statistical power analyses to determine that the number could “show differences between the meals reliably.”
She also explained that while the funding came from HAB and she is part of the organization’s advisory group, “HAB was not involved with our study design or interpretation of results.”
Yet hers is not the only study to receive such funding.
In fact, HAB has backed a number of frequently cited avocado studies, including one linking consumption of the fruit to a reduction in the risk of developing metabolic syndrome, a critical review of the potential health effects of the Haas avocado, and a study with 26 volunteers, who reported feeling less hungry after the addition of half an avocado to their midday meal.
If avocados leave you feeling cold, or studies with industry backing get your hackles up, other food sources provide the much-desired fat and fiber combination.
As Burton-Freeman told MNT: “Nuts are another whole food that delivers healthy fat and fibers. Fats and fibers can be paired in formulated products, but avocados and nuts are examples of plant foods that contain both inherently.”