Satiety Signals: Knowing When to Stop

WITH the world's expanding waistline showing no signs of shrinking, the diet industry continues to be big business. Approximately 1.6 billion adults aged 15 and over are considered overweight and at least 400 million obese1, creating a growing weight loss and management market.

The international weight management market was worth an estimated $7.3bn in 2009, and it is set to grow year-on-year at between 6 to 8 per cent for the next five years, according to the report "The Future of the Weight Management Market" from Leatherhead.

Leatherhead says the direction of the industry is shifting from 'better for you' products (i.e. diet and low and light foods), however, towards functional weight management products providing consumers with differentiation and added value, as well as fuelling innovation and growth within this market. Manufacturers are now moving away from the traditional drivers of innovation in health and weight management - reducing the fat, salt and sugar content of foods - and exploring products with added benefits such as hunger management.

Growth so far has largely been due to innovations within the bakery and cereals and the beverage markets, which currently hold shares of 33.5% and 28.4%, respectively.
Beverages and cereals remain the most prolific sectors for weight management claims across the globe. Leatherhead notes that this is largely due to the functionality of the products, i.e. their ability to 'carry' other ingredients well, as well as the fact that consumers generally perceive them as both convenient and healthy.

Mindful Eating

Eating quickly is associated with overeating, as a number of studies have established. In the last few years, research regarding gut hormones has shown that their release after a meal acts on the brain and induces satiety and meal termination. More recently, researchers have examined how different rates of eating impact the release of the appetite-regulating hormones, such as peptide YY (PYY) and glucagon-like peptide (GLP-1).

In this study2, subjects consumed the same test meal, 300ml of ice cream, at different rates. Researchers took blood samples for the measurement of glucose, insulin, plasma lipids and gut hormones before the meal and after the beginning of eating at 30-minute intervals until the end of the session, 210 minutes later. Researchers found that subjects who took the full 30 minutes to finish the ice cream had higher concentrations of PYY and GLP-1 and also tended to have a higher fullness rating.

Alexander Kokkinos, MD, PhD, of Laiko General Hospital in Athens, Greece and lead author, commented that the findings provide an insight into an aspect of modern-day food over-consumption. "Many people, pressed by demanding working and living conditions, eat faster and in greater amounts than in the past," said Dr Kokkinos. "The warning we were given as children that 'wolfing down your food will make you fat,' may in fact have a physiological explanation."

Role of Proteins in Staving Cravings

A University of Missouri researcher has found that eating a healthy breakfast, especially one high in protein, increases satiety and reduces hunger throughout the day. In addition, using functional magnetic resonance imaging (fMRI) the researchers found that eating a protein-rich breakfast reduces the brain signals controlling food motivation and reward-driven eating behaviour.

"This research provides additional evidence that breakfast is a valuable strategy to control appetite and regulate food intake," said Heather Leidy, assistant professor in the MU Department of Nutrition and Exercise PhysAir Force 1 High