13 November 2011

Eating Pace and Protein to Control Overeating

One matter that most evidence-based nutritionists and dietitians will agree on is that humans have evolved to be experts in the task of seeking out palatable foods, which generally contain a combination of sugar, fat, and salt. These nutrients, usually scarce over the long span of evolutionary time and highly valued, are what helped lead to the development of our senses.

Nowadays, it is still the sight, aroma, and taste of food powered by sugar-fat-salt reward and satisfaction that still guides our eating decisions, except in a modern environment of widely available food and sedentary lifestyles.

The axe that nutritionists have to grind with food manufacturers is the blatant targeting of our senses with   layer upon layer of bold sugar-fat-salt flavors -- think of potato chips dipped in artichoke dip, French fries and ketchup, pizza topped with pepperoni, and so on. According to David Kessler, these foods are so powerfully appealing to our senses that they may even alter our brain chemistry driving our appetites for more.
In any case, any nutritionist should agree, these processed foods being higher in sugar, fat, salt also usually come at the expense of other nutrients like protein, fiber, vitamins, and minerals.

With the holidays around the corner, it's the time of year when folks look for advice on how to avoid putting on 10 or more pounds by the new year. Recently, a couple of studies offer a couple of possible pointers on what might help folks still enjoy the festivities but control their appetites well enough to stay on track with their health and weight-management goals.

Pay attention to percent protein  

Eating foods with a higher percent of calories from protein could help control appetite, according to new randomized controlled experiment published in PLoS One (1). Scientists tested "the protein leverage hypothesis" on lean men and women by feeding them foods with similar palatability but with macronutrient composition disguised under ad libitum (all you can eat) conditions. They studied the subjects over four-day periods with fixed menus containing either 10, 15, or 25 percent calories from protein.

The scientists noted that subjects eating a 10 percent protein diet ate an average of 12 percent more calories over the four days, almost 60 percent of which came from savory foods. Seventy percent of the caloric increase came from eating "snack foods." If the subjects on the 10 percent protein diet kept at it, without an increase in energy expenditure from increased activity, they'd likely put on about 2 pounds of weight per month, the scientists report.

“In our study population a change in the nutritional environment that dilutes dietary protein with carbohydrate and fat promotes overconsumption, enhancing the risk for potential weight gain,” the authors wrote.

Pace yourself when you eat

Another pointer is to take time to really enjoy foods. Yet two more studies, presented at the Obesity Society in Orlando this month, (2) suggest that there may just be something to the idea of eating more slowly to help control calories, although I realize that the evidence of these may have similar problems of earlier studies' methodology. The studies found that men usually ate faster than women, heavier faster than lighter, and that refined grains were eaten faster than whole grains (whole grains require more chewing because they're more fibrous).

"It takes time for your body to process fullness signals," said lead researcher Kathleen Melanson in a press release, "so slower eating may allow time for fullness to register in the brain before you've eaten too much."

Previously, Melanson's lab was the first to find in 2007 that eating slowly actually led people to eat fewer calories overall. In that study, women who were told to eat slowly, pausing between bites and chewing slowly, ate about 10 percent fewer calories.

How our ancestors ate

Looking back on how our ancestors ate, the majority of their diet being lean meats combined with fibrous fruits and vegetables, it only makes sense that the pointers above could help keep us in line with a style of eating more appropriate for our genetic make-up.

Paying more attention to the percent of protein in foods (and fiber too) and how fast foods are eaten could help cut calories and the weight off. The higher percent of protein in a meal and eating over a longer period of time might also help with maintaining healthy blood sugar levels.

With an abundance of highly palatable goodies available these days, especially during the holidays, it's worth keeping in mind these strategies to help guard against how fat, sugar and salt affect our brains and compel us to overeat.


1. Gosby AK, Conigrave AD, Lau NS et al. Testing protein leverage in lean humans: a randomised controlled experimental study. PLoS One 2011;6:e25929. doi:  10.1371/journal.pone.0025929
2. McLeish T. Researcher provides further evidence that slow eating reduces food intake. University of Rhode Island. 2011.

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