March 14, 2022 -- Eat french fries every day for a month? Sure, as long as it's for science.
That's exactly what 107 people did in a scientific study, while 58 others ate a daily serving of almonds with the same number of calories.
At the end of the study, the researchers found no significant differences between the groups in people’s total amount of fat or their fasting glucose measures, according to the study, which was published last month in The American Journal of Clinical Nutrition.
The french fry eaters gained a little more weight, but it was not statistically significant. The people who ate french fries gained 0.49 kilograms (just over a pound), vs. about a tenth of a kilogram (about one-fifth of a pound) in the group of people who ate almonds.
"The take-home is if you like almonds, eat some almonds. If you like potatoes, eat some potatoes, but don't overeat either,” says study leader David B. Allison, PhD, a professor at Indiana University’s School of Public Health in Bloomington. “It's probably good to have a little bit of each -- each has some unique advantages in terms of nutrition."
"This study confirms what registered dietitian nutritionists already know -- all foods can fit. We can eat almonds, french fries, kale, and cookies,” says Melissa Majumdar, a registered dietitian and certified specialist in obesity and weight management at Emory University Hospital Midtown in Atlanta. “The consumption of one food or the avoidance of another does not make a healthy diet.”
At the same time, people should not interpret the results to mean it's OK to eat french fries all day, every day. "We know that while potatoes are nutrient dense, the frying process reduces the nutritional value," Majumdar says.
"Because french fries are often consumed alongside other nutrient-poor or high-fat foods, they should not be consumed daily but can fit into an overall balanced diet," Majumdar says.
Would You Like Fries With That?
The researchers compared french fries to almonds because almonds are known for positive effects on energy balance, body composition, and low glycemic index. The research was partly funded by the Alliance for Potato Research and Education.
French fries are an incredibly popular food in the United States. According to an August 2021 post on the food website Mashed, Americans eat an average of 30 pounds of french fries each year.
Although consumption of almonds is increasing, Americans eat far less in volume each year than they do fries -- an estimated 2.4 pounds of almonds per person, according to August 2021 figures from the California Almond Board.
Allison and colleagues recruited 180 healthy adults for the study. Their average age was 30, and about two-thirds were women.
They randomly assigned 60 people to add about a medium serving of plain french fries (Tater Pals Ovenable Crinkle Cut Fries, Simplot Foods) to their diet. Another 60 people were assigned to the same amount of Tater Pals fries with herbs (oregano, basil, garlic, onion, and rosemary), and another 60 people ate Wonderful brand roasted and salted almonds.
Investigators told people to add either the potatoes or nuts to their diet every day for a month and gave no further instructions.
After some people dropped out of the study, results were based on 55 who ate regular french fries, 52 who ate french fries with herbs and spices, and 58 who ate the nuts.
The researchers scanned people to detect any changes in fat mass. They also measured changes in body weight, carbohydrate metabolism, and fasting blood glucose and insulin.
Changes in total body fat mass and fat mass were not significantly different between the french fry groups and the almond group.
In terms of glycemic control, eating french fries for a month "is no better or worse than consuming a caloric equivalent of nuts," the researchers note.
Similarly, the change in total fat mass did not differ significantly among the three treatment groups.
Adding the herb and spice mix to the french fries did not make a significant difference on glycemic control, contrary to what the researchers thought might happen.
And fasting glucose, insulin, and HbA1c levels did not differ significantly between the combined french fry and almond groups. When comparisons were made among the three groups, the almond group had a lower insulin response, compared to the plain french fry group.
Many different things could be explored in future research, says study co-author Rebecca Hanson, a registered dietitian nutritionist and research study coordinator at the University of Alabama at Birmingham. "People were not told to change their exercise or diet, so there are so many different variables," she said. Repeating the research in people with diabetes is another possibility going forward.
The researchers acknowledge that 30 days may not have been long enough to show a significant difference. But they also note that many previous studies were observational while they used a randomized controlled trial, considered a more robust study design.
Senior author Allison emphasized that this is just one study. "No one study has all the answers."
"I don't want to tell you our results are the be all and end all or that we've now learned everything there is to learn about potatoes and almonds," he says.
"Our study shows for the variables we looked at … we did not see important, discernible differences," he says. "That doesn't mean if you ate 500 potatoes a day or 500 kilograms of almonds it would be the same. But at these modest levels, it doesn't seem to make much difference."
The study was funded by grants from the National Institutes of Health and from the Alliance for Potato Research and Education.
Asked if the industry support should be a concern, Majumdar said, "Funding from a specific food board does not necessarily dilute the results of a well-designed study. It's not uncommon for a funding source to come from a food board that may benefit from the findings. Research money has to come from somewhere."
"This study has reputable researchers, some of the best in the field," she said.
The U.S. produces the most almonds in the world, and California is the only state where almonds are grown commercially. Asked for the almond industry's take on the findings, "We don't have a comment," said Rick Kushman, a spokesman for the California Almond Board.