According to one large study in 9,075 people, having higher blood levels of vitamin B12 was associated with a lower risk of obesity ( Similarly, another study in 976 people showed that having low levels of vitamin B12 was linked to a higher risk of overweight or obesity ( Whats more, a study in 256 children showed that children with lower levels of vitamin B12 tended to have a higher body mass index (BMI), which is a measure of body size determined by height and weight ( However, keep in mind that while these studies show an association between vitamin B12 status and body weight, they dont take other potentially contributing factors into account
2 Institute of Medicine (1998) Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline
Some studies indicate people with obesity have low vitamin B12 levels
Weight fluctuates daily due to water retention, food volume, and hormonal cycles, so weekly averages provide better data than daily numbers