This study looked at the relationship between magnesium intake and incidence of obesity in 5,115 American young adults over a 30-year period. The participants were recruited in 1985-1986 and followed for 30 years. Dietary evaluations were done in 8 follow-ups. Peanuts and peanut butter are excellent sources of Magnesium. The vitamin is also found in seeds, whole grains, legumes, and dark-green vegetables.