Undercover vegetables

25 September 2012

It's not only warfare using stealth technology, says Associate Professor Tim Crowe.

It’s not just in the world of warfare that stealth technology is being employed, writes Deakin University's Associate Professor Tim Crowe on his blog Thinking Nutrition.

The idea of stealth has now been applied to the humble vegetable. Covertly adding pur?ed vegetables into foods can not only increase the nutritional quality of the meal, but also help reduce the amount kilojoules eaten which is good news for your health and waistline.

The link between the energy density of food and the risk over-consumption is well known to scientists. Energy density is a measure of the kilojoule content of food per gram. Foods like lettuce and celery are the least energy dense foods normally eaten, while at the other end of the scale, chocolate and foods high in fat or sugar are the most energy dense.

We usually prefer to eat a fixed weight of food to give us the pleasant feelings of fullness. Knowing how our physiology works, then choosing foods low in energy density can give similar feelings of fullness to higher energy dense foods, but without all the extra kilojoules.

One way to reduce the overall energy density of a person’s regular diet is to simply eat more vegetables. Vegetables are typically high in water and fibre and low in fat. They are also filling and help displace more fattening foods from the plate.

Getting kids to eat vegetables is hard enough; promoting the merits of eating more veggies to adults is even harder. Not to be deterred, food researchers who have built their career on studying energy density and its effect on food consumption have designed a novel approach of sneaking in pur?ed vegetables into regular food items.

In the latest research published in the high-impact American Journal of Clinical Nutrition, a group of healthy adults ate all of their meals on a single day in a science laboratory and repeated this weekly for three weeks. Without the volunteers knowing, they were presented with a range of entr?es, some of which were ‘adulterated’ with pur?ed vegetables. Each person rated their feelings of hunger and fullness before and after every meal, with researchers recording the quantity of food eaten at each meal.

Consistent with much of the previous research in this area, the volunteers tended to eat a fixed weight of food regardless of the energy density of the meals. Because adding vegetables to an entr?e lowered its energy density, there was a significant reduction of up to 1500 kJ (357 Calories) when people were fed this meal compared to the regular entr?e.

Even though less kilojoules were eaten in a sitting, feelings of hunger and fullness after the vegetable-rich entr?e were the same as that for the regular dish. The good news was that the palatability of the different entr?e dishes rated as comparable whether vegetables were added or not.

Want to get more veggies into your own and the diets of those you cook for? Whether by stealth or creative naming of a dish,  blend them into the foods that you already love, rather than present them as lonely orphans on the side of the plate.

Associate Professor Tim Crowe The idea of stealth has now been applied to the humble vegetable, says Associate Professor Tim Crowe.

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