For the past 30 years most of my research has been focused on investigating the potential health benefits of various dietary components or food patterns, which have been explored in the context of randomized controlled trials in free-living adult populations. Some of the interventions have involved vegetarian diets, soy foods and soy food components, garlic, omega-3 fats/fish oil/flax oil, antioxidants, Ginkgo biloba, and popular weight loss diets. These trials have ranged in duration from 8 weeks to a year, with study outcomes that have included weight, blood lipids and lipoproteins, inflammatory markers, glucose, insulin, blood pressure and body composition. Most of these trials have been NIH-funded. The most impactful of these was an NIH funded weight loss diet study - DIETFITS (Diet Intervention Examining The Factors Interacting with Treatment Success) that involved randomizing 609 generally healthy, overweight/obese adults for one year to either a Healthy Low-Fat or a Healthy Low-Carb diet. The main findings were published in JAMA in 2018, and many secondary and exploratory analyses are in progress testing and generating follow-up hypotheses.
In the past few years the long-term interests of my research group have shifted to include three additional areas of inquiry. One of these is Stealth Nutrition. The central hypothesis driving this is that in order for more effective and impactful dietary improvements to be realized, public health professionals need to consider adding non-health related approaches to their strategies toolbox. Examples would be the connections between food and 1) global warming and climate change, 2) animal rights and welfare, and 3) human labor abuses (e.g., slaughterhouses, agriculture fields, fast food restaurants). An example of my ongoing research in this area is a summer Food and Farm Camp run in collaboration with the Santa Clara Unified School District since 2011. Every year ~125 kids between the ages of 5-14 years come for 1-week summer camp sessions led by Stanford undergraduates and an Education Director to tend, harvest, chop, cook, and eat vegetables...and play because it is summer camp! The objective is to study the factors influencing the behaviors and preferences that lead to maximizing vegetable consumption in kids.
A second area of interest and inquiry is institutional food. Universities, worksites, hospitals, and schools order and serve a lot of food, every day. If the choices offered are healthier, the consumption behaviors will be healthier. A key factor to success in institutional food is to make the food options "unapologetically delicious" a term I borrow from Greg Drescher, a colleague and friend at the Culinary Institute of America (the other CIA). Chefs are trained to make great tasting food, and chefs in institutional food settings can be part of the solution to improving eating behaviors. In 2015 I helped to initiate a Stanford-CIA collaboration that now ~70 universities that have agreed to collectively use their dining halls as living laboratories to study ways to maximize the synergy of taste, health and environmental sustainability (Menus of Change University Research Collaborative - MC-URC). If universities, worksites, hospitals and schools change the foods they serve, they will change the foods they order, and that kind of institutional demand can change agricultural practices - a systems-level approach to achieving healthier dietary behaviors.
The third area is diet and the microbiome. Our lab has now partnered with the world renowned lab of Drs. Justin and Erica Sonnenburg at Stanford to conduct multiple human nutrition intervention studies that involve 1) dietary intervention, 2) microbiome characterization, and 3) outcomes related to inflammation and immune function. The most impactful of these studies was the Fe-Fi-Fo study (Fermented and Fiber-rich Foods) study published in Cell in 2021. In that 10-week intervention, study participants consuming more fermented foods increased their microbial diversity and decreased blood levels in almost 20 inflammatory markers. Our ongoing Maternal and Offspring Microbiome Study (MOMS) is examining the transfer of the maternal microbiome to the infant among 132 pregnant women randomized to increase fiber, or fermented food, or both or neither for their 2nd and 3rd trimester; the infants will be tracked for 18 months.
My long-term vision in this area is to help create a world-class Stanford Food Systems Initiative and build on the idea that Stanford is uniquely positioned geographically, culturally, and academically, to address national and global crises in the areas of obesity and diabetes that are directly related to our broken food systems.