This Week's Nutrition News Feed
In this week's news: Parents get schooled about the healthfulness of home versus school lunches; weight-loss study tips the scales in favor of vegan diet; and researchers suggest attempts to reset metabolism are likely futile.
Parents like to think the lunches they pack for their kids are way healthier than the school lunches they love to complain about, but guess what? A new study, published in Journal of Nutrition Education and Behavior, suggests just the opposite is true. After analyzing the nutritional value of 560 home-packed lunches brought in by pre-K and kindergarten students at three different schools and comparing them to 750 school lunches, the researchers concluded that the "packed lunches were of less nutritional quality than school lunches," according to the study’s lead researcher. While some lunches were healthier than others, overall, the packed lunches were higher in calories, fat, saturated fat and sugar, as well as in vitamin C and iron, than school lunches and lower in protein, fiber, vitamin A and calcium, as well as sodium, than school lunches. The packed lunches were also less like to contain fruits, vegetables, sugar-free juice and milk and more likely to contain chips, crackers and other snacks than school lunches.
If you want to lose weight, think (and eat) plants. A new study has found that people who followed a strict vegan diet, eating no meat or animal products, shed more pounds than those following any of four other diets: semi-vegetarian (eating meat only occasionally), pesco-vegetarian (eating no meat except seafood), vegetarian (eating no meat or seafood, but eating animal products), and omnivorous (with no foods excluded). Those following the strictly vegan diet also had lower levels of saturated and unsaturated fat, lower BMIs and improved macro nutrients, researchers reported. Also of note: The vegan participants lost weight and enjoyed the other health benefits even though they freely consumed carbs. "We've gotten somewhat carb-phobic here in the U.S. when it comes to weight loss,” lead author Gabrielle Turner-McGrievy observed. "This study might help alleviate the fears of people who enjoy pasta, rice and other grains but want to lose weight."
Can you train your body to maintain a higher metabolism? Sure would be nice if you could, but a new study, presented recently at the Obesity Society's annual meeting, suggests that the answer is, alas, no. Researchers found that healthy participants who were overfed high-, normal- and low-protein diets all gained similar amounts of weight, but that those who ate normal- and high-protein diets had a higher metabolism and stored 45 percent of the excess calories they consumed as lean tissue (a.k.a. muscle) mass, while participants fed a low-protein diet stored 95 percent of the excess calories they consumed as body fat. The study also showed that the metabolic uptick seen by those eating a higher-protein diet was not sustainable when these participants switched to a normal-protein diet, which suggests, researchers say, that "the human body cannot be trained to maintain a higher metabolism." Oh, well.