With the holidays behind you and New Years’ Resolutions in tow, take the opportunity to reevaluate your meal structure!  As part of a weight loss or weight management lifestyle strategy, it is often recommended to eat small, frequent meals, rather than having three squares a day.   A recent study, which examined the 24 hour trends in an important hormone called PYY,  sheds some new light on why small frequent meals may be so effective to curb hunger and help prevent overeating.

PYY is a hormone secreted by the gastrointestinal tract in response to a meal.  When released, PYY stimulates a sense of fullness by slowing down the emptying of the stomach, and stimulating the ‘fullness centre’ in the hypothalamus of the brain.  Additionally, PYY may also increase overall metabolic rate, thereby increasing our overall calorie burn.

The study, conducted by Brenna Hill and colleagues at Pennsylvania State University, looked at levels of PYY in normal weight young women over a 24 hour period.  Study participants were fed standardized meals as breakfast at 9:00AM, lunch at 12:00PM, supper at 6:00PM, and a snack at 9:00PM.  There was no significant difference in caloric content of the three main meals.

As expected, the results showed that PYY peaks after each meal.  Interestingly, over the entire 24 hour period, the highest level of PYY was seen after lunch.  On further examination, it became evident that this high lunch time peak was due to the fact that there was an additive effect leftover from the PYY increase following the breakfast meal, which was consumed just 3 hours prior to lunch.  In other words, PYY levels had not had the chance to decrease back to baseline following breakfast by the time that study participants ate lunch.  As the supper time meal was consumed 6 hours after lunch, there was a longer duration of time for PYY to settle out, such that the peak level achieved after supper was not as high as the post lunch level.

It would follow, then, that if a person ate frequently throughout the day, that the PYY may remain elevated throughout the day, thereby keeping hunger at bay and helping to control food intake.  This is a hypothesis only, and needs to be tested in further study; other factors such as the caloric content and composition of each meal would need to be considered as well.   In order to make small frequent meals work in the battle of the bulge, these frequent meals need to be substantially lower in calorie count compared to the eating pattern of eating three squares, such that the overall calorie consumption should ideally be lower over 24 hours compared to eating three full meals.

The current study lends support to the idea that eating small frequent meals is a better eating strategy than eating three major meals, and I look forward to seeing what evolves in this interesting area of research!

Note for patients taking medication to treat diabetes: It is important to discuss any possible change in eating habits with your doctor, before making any dietary changes.  Some medications that treat diabetes, including some oral medications as well as insulin, are dosed to control your blood sugar after a meal.  These medications may need adjustment with a change in eating plan.  For patients using meal time insulin, some types of mealtime insulin are easier to incorporate into a smaller, more frequent meal plan than others – talk to your doctor and your diabetes health care team to work out a plan especially for you!

Dr. Sue © 2012   www.drsue.ca     drsuetalks@gmail.com

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