Many biological systems depend on vitamin D. Kenney says its insufficiency is connected to poor metabolic health, which burns calories, reduced insulin sensitivity,
which controls blood sugar, and altered leptin levels, which regulate appetite. If we don't get enough, we may burn less calories and eat more, which is bad for weight reduction.
This B vitamin "plays an important role in the metabolism of your fat through your liver," adds Keanevey. "Some research shows that low vitamin B12 levels contribute to weight gain and obesity."
Those who eat largely plants may struggle to acquire enough B12. We get most of this vitamin from meat and seafood. If you eat vegan or vegetarian, talk to your doctor about supplements.
The body uses this vitamin for several functions. Keanevey said zinc helps convert carbs and fats into energy.
It may also help preserve lean muscular mass, which burns more calories than fat. Thyroid hormone production requires zinc, which is essential to metabolism. It also helps heal wounds and affects taste and smell.
Magnesium helps relax and sleep, "two things which are necessary for healthy weight loss," adds Kenney, making it increasingly popular. Food processing and energy production are also its functions. "Low magnesium levels increase inflammation, which can cause weight gain."
This little addressed vitamin is crucial for thyroid function. The thyroid produces hormones and regulates metabolism. Kenney said hormone synthesis might cause weight gain without enough iodine. Interestingly, manufactured meals contain iodized salt, therefore iodine deficiency is rare. It is also in tuna, oysters, shrimp, seaweed, eggs, and milk.