JEFFREY BLUMBERG: "Evidence-based Nutrition: The Problem of Proof"
Over the last decade, randomized clinical trials (RCTs) of dietary supplements and nutritional interventions for major disease entities have largely resulted in null or negative outcomes - despite having positive results from various studies. Because RCTs have traditionally been accepted as the "gold standard" for establishing cause-and-effect relationships, these studies have led to skepticism about the importance of specific nutrients or nutrient combinations in health and disease. Nonetheless, the foundation of RCTs in evidence-based medicine has now been wholly adopted in the creation of nutrition and science policy. Although this is one approach toward understanding the efficacy of nutrient interventions, the complexities of nutrient actions and interactions cannot always be adequately addressed through a single research design. Advancing evidence-based nutrition from its current version to one based upon more relevant and realistic criteria will depend upon research approaches that include RCTs but go beyond them.
WALTER WILLETT: “Diet and Health: A Progress Report”
For most of the last 20 years the focus of nutritional advice has been to reduce total fat intake and consume large amounts of carbohydrate. However, this advice is inconsistent with many lines of evidence indicating that unsaturated fats have beneficial metabolic effects and reduce risk of coronary heart disease. More recent evidence has also shown that the large majority of carbohydrates in current industrial diets, consisting of refined starches and sugars, have adverse metabolic effects and increase risks of obesity, heart diseases and type 2 diabetes. Thus, in what appears to be an optimal diet, most calories would come from a balance of whole grains and plant oils, proteins would be provided by a mix of beans, nuts, fish, eggs, and poultry, and the remaining nutritional needs would be filled by plenty of vegetables and a few fruits. Important considerations include the role of dairy products, the interrelationships with physical activity and genetic variations, the implications of our food choices on environmental sustainability, and how we move from today's pathological diet to a more optimal way of eating.