Here's the research behind the numbers you see on our site.

Protein

• MedlinePlus: Protein in Diet
• MedlinePlus: Amino Acids
• Rutherfurd: Dairy and Whey Protein Quality
• Mathai: Whey vs. Plant Protein Quality

Vitamins

• NIH: Vitamin D Fact Sheet
• NIH: Vitamin C Fact Sheet
• FDA: Daily Values on Labels

Sugar

• AND/ACSM: Sports Nutrition Position
• Nouri: Whey Protein and Blood Sugar

Kids' nutrition

• Abbott: Protein Deficiency in Kids
• Elango: Children's Protein Needs
• Hudson: Protein Requirements in Children
• Burstad: Protein and Amino Acid Needs
• Dietary Guidelines for Americans
• CDC Growth Charts
• USDA FoodData Central