Mouth Feel Could Be Key To Weight Loss

High orosensory exposure associated with early insulin response

With Marlou Lasschuijt MSc and Amy Hess Fischl MSc

A recent study by lead author Marlou Lasschuijt, MSc at Wageningen University & Research in the Netherlands, suggests that differences in orosensory exposure of food may reduce food intake, ultimately leading to weight loss.

Orosensory perceptions refer to the physical sensation of food in the mouth and are part of the cephalic phase of digestion. Foods with a lot of texture that require chewing before swallowing have a high orosensory exposure, while those with little texture that require less effort to consume have a low orosensory exposure. 

Study details

The Lasschuijt study sought to determine if orosensory exposure (high vs low) and/or eating rate (fast vs slow) influenced satiation, food intake, or changed the digestive endocrine response during this early digestive phase. The researchers used a 2x2 cross-over study design recruiting 60 young healthy males total. Twenty participants were used for blood draws to measure changes in insulin, pancreatic polypeptide (PP), and ghrelin preprandial, at the start of the meal, and postprandial.

Participants were given a chocolate custard with either caramel sauce (Low exposure; LE) or with caramel pieces (High exposure; HE). They were instructed to either wait either 5 or 15 seconds between bites to regulate a fast (FE) or slow (SE) eating rate. A Visual Analog Scale (VAS) was used to determine feelings of satiety, fullness, and desire to eat before and after eating the custard.

Slowly eating a high exposure food increases feelings of fullness

The VAS results found that those in the High exposure/slow eating (HE/SE) rate paradigm felt full more quickly and had the lowest desire to continue eating by the end of meal compared to those in the Low exposure/fast eating rate (LE/FE). Within 15 minutes after the meal, the LE/FE reported higher feelings of hunger and a greater desire to eat again than the HE/SE group.

Overall, those given the High exposure custard ate 19-22% less food than those given the Low exposure custard regardless of eating rate. Eating rate also had a main effect suggesting that simply slowing down the rate of eating decreased food intake by 20-26%. Thus, a stronger feeling of satiety and an actual reduction in food intake was associated with a higher orosensory exposure and a slower eating rate.

Endocrine Web reached out to Amy Hess Fischl MS, RDN, LDN, BC-ADM, CDE, Department of Pediatric and Adult Endocrinology at the University of Chicago to find out her opinion on this study. She stated that it was an interesting idea which reminded her of similar work by Barbara Rolls PhD at Pennsylvania State University on volumetrics in nutrition. Ms. Fischl summarized the work by saying, “The premise is more volume of lower calorie items increases the time it takes to finish eating and consequently increases satiety. So, the longer it takes anyone to finish a meal, inevitability we see a reduction in calories and impact on glucose.”

High orosensory exposure was associated with early insulin response

Endocrine changes, specifically in blood insulin and PP, early in the digestive process have been reported previously. The current study explores if the early endocrine response changes as a function of orosensory exposure and eating rate.

Insulin levels rose significantly within 10 minutes of starting the meal in all groups, however in the HE/SE group insulin levels were 81% higher than the LE/FE group postprandially. The rate of insulin increase in the HE/SE participants rose 19.5% for every 10g of food consumed as compared to 8.1% in the LE/FE participants. The change in insulin levels in this early phase, prior to nutrient absorption, is consistent with other findings as well as increased release with longer meal length. This is the first report on the effects of orosensory input affecting insulin release.

PP is an anorectic hormone that rises postprandially to signal satiety. It is associated with a lower food intake and a reduction in gastrointestinal mobility. In the Lasschuijt study, this peptide rose more slowly in the HE/SE group compared to the LE/FE which seems to contradict the current consensus of PP function.

The authors state, “An explanation for the early increase in PP in the low-OSE, fast-ER condition observed in this study might be the endocrine ‘break’ function.” The “break” function has been described as an endocrine response attempting to slow down intake to allow the body time to process the incoming food, as when food is eaten too quickly.

Ghrelin is a hormone associated with increasing food intake, gastrointestinal mobility, and gastric emptying. Circulating levels of this hormone can double before a meal and then decrease in the hour or so after. In the present study, ghrelin levels were not significantly altered at any time point in any condition compared to baseline. Previous work manipulating eating rate alone also found no change in ghrelin. This lack of change, however, should be interpreted in light of data that suggests preprandial elevations in ghrelin levels are circadian control and conditioned by standardized meal times, rather than orosensory or gastric stimulation alone. 

Thus, the orosensory exposure of a food and the time to consume that food may initiate an early insulin response prior to little or no nutrient absorption. Changes in PP support the notion that a fast eating rate may trigger a “break” function designed to slow down the rate of eating.

Application for patients dealing with obesity, prediabetes, and diabetes 

Even though the Lasschuijt study used healthy male subjects, Ms. Fischl agrees that there are some take-home points for individuals at risk for diabetes. Since insulin differences were the most prominent endocrine changes related to orosensory exposure, we asked her to comment whether this effect might still be seen in diabetics. She told us:

“As for the insulin response, that is very individualized, based on duration of diabetes, among other things. If it takes a little longer to finish a meal then less likely we will see a smaller insulin response. And of course the amount of carbs would affect this as well, but we also see that adding protein and fat slows digestion and reduces glycemic impact.”

We asked a similar question of the lead author, Marlou Lasschuijt, MSc, who said:

“Eating slow would give more time for insulin to increase prior to ending the meal. Additionally, many studies have shown that eating slow, due to hard textured foods, decreases food intake. As many type 2 diabetic patients are overweight, I think increased orosensory duration through harder food texture would be beneficial both for blood glucose homeostasis and weight loss.”

In the end, individuals at risk for diabetes and those already diagnosed have many options to help them lose weight and eat healthy meals. The results of this research, that textured food and slower eating reduce food intake, provide another useful tool in the diabetic tool box. In other words, when faced with different food choices, encouraging patients to pick crunchy over creamy foods may be one small step toward supporting their weight loss and healthy lifestyle. 

Dr. Bjugstad and Ms. Lasschuijt report no conflicting interests on the presented topics. Ms. Fischl reports financial interests with Abbott and Xens Pharmaceuticals.

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