MyPlate is the replacement for the food pyramid most people are familiar with. This website has good resources to help you make better choices regarding your nutrition.
The Harvard Nutrition Source has a plethora of credible nutrition information that is based on sound scientific research.
The CDC Healthy Living Website has a variety of credible information on various health topics.
The American College of Sports Medicine is the premier authority on physical activity. Their website has a lot of information on exercise and how it affects health.