Grains and vegetables keep you healthy and prevent serious systemic diseases. Meat and dairy push you in the other direction.
Dr. Michael Greger runs a YouTube channel called NutritionFacts.org which is based on this reading of hundreds of scientific papers on nutrition every year and then puts it into plain English.
If it looks like he's walking while talking, he is. He's walking on a treadmill. Way better for you than sitting around.