Chewing Less, Gaining More: A Weight Gain Effect of Ultra-Processed Food

Here is some concerning news: more than half of the calories adults eat at home now come from ultra-processed foods and previous research has demonstrated that if you eat a diet based largely on ultra-processed foods (UPFs), you are likely to consume far more calories than you would eating fewer of them–and not even notice that you are overeating. One reason for this uptick in calories and the potential weight gain that can come with it, might be that heavily processed foods spend less time in our mouths.

In a randomized, crossover study published in the journal Diabetes, Obesity & Metabolism, the effects of UPFs versus non-UPFs on body weight, calorie (energy) intake, metabolism and chewing frequency in overweight and obese males were investigated. For one week, participants were provided with a food diet consisting mostly of UPFs or non-UPFs that was followed by a two-week washout period and then another week of eating an alternative diet to the first week. During the UPF period, the Japanese participants gained an average of 2.4 pounds and ate 814 additional calories compared with the non-UPF period. The investigators also determined that the number of chews per calorie was significantly lower when people ate the UPF diet. UPFs typically have a softer texture and contain less fiber so require less chewing. And less chewing can result in fewer satiety signals and a quicker rate of calorie consumption making it easier to overeat and tip the scale into a calorie access that contributes to unwanted weight gain. So encouraging your clients who are interested in dropping some weight to gravitate towards foods that require more oral grinding seems like sage advice.