Instead, they provided plants and animal protein that were seasonal and more closely resembled what grizzlies find in the wild. (As Natterson-Horowitz pointed out, there are no banana or mango plantations in the Canadian Rockies.) They chose vegetables and fruits such as kale, peppers, celery, heirloom apples — all more fibrous and seedy than the bears’ previous diet. And they replaced the hamburger meat with whole prey, such as fish and rabbits, which the grizzlies had to work harder to disassemble and eat.
They stopped placing food in the cages on a set schedule; they hid meals and added wax-worm snacks to the bears’ peaty foraging piles, which made the grizzlies burn calories as they rooted for each desirable morsel.
With this approach, the bears shed hundreds of pounds over the course of a year, leading Natterson-Horowitz to wonder whether a similar alterations in a human’s environment might be equally effective.
“I went into my freezer and saw that I had four frozen chickens in the back. There is something comforting about that. Vets call it food caching,” or hoarding, says Natterson-Horowitz, adding that all animals are hard-wired to hoard food.
She realized that one easy way to limit access to abundance — and, by extension, the tendency to overeat or eat too often — is to empty food caches at work, in the glove compartment and in the purse, and to shop for at most a few days’ worth of meals instead of stockpiling.
In choosing foods, she said, she focused less on certified organic foods and more on selecting ones that were seasonal, locally grown and less processed.
Research suggests that fruit and vegetables typically found in supermarkets are bred for shelf life and their ability to withstand transport but are often less
nutritious and more caloric than traditional heirloom varieties. The Biochemical Institute at the University of Texas at Austin tracked the nutrient content of 43 of the most frequently cultivated varieties of produce from 1950 to 1999 and found a substantial reduction in protein content, B vitamin, fiber and antioxidants over that period.
Similarly, traditional whole grains such as quinoa, faro and barley are more filling and offer up fewer calories and more nutrition per mouthful than refined wheat and white rice. In general, these traditional foods also encourage the digestive system to work hard for each calorie.
Better gut bacteria
In addition to having lower sugar, more fiber and more nutrients, these heirloom and traditional foods tend to nurture a healthier assortment of intestinal bacteria, says Stanford School of Medicine microbiologist Justin Sonnenburg. “Basically, even though most of us are eating in a modern way, our genome is optimized to work with the microbiota [intestinal bacteria] that are promoted by traditional foods.”