Maybe you’ve heard about taking vitamin D to ease depression, treat acne, or even help ease COVID-19 symptoms. But now people are talking about vitamin D for weight loss?!

No, it’s not just another fad. There’s actually a decent amount of evidence that shows a correlation between vitamin D levels and weight loss.

Here’s the deal on the link between adding some D and weight loss.

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Vitamin D is a fat-soluble vitamin you can get from some foods or supplements. Your bod can also make it when you soak up the sun Sheryl Crow-style.

Vitamin D is vital for:

  • maintaining strong bones and teeth
  • keeping your immune system working at its best
  • helping your body properly absorb calcium and phosphorus

Since not many foods naturally contain vitamin D, many health professionals recommend that adults get 5 to 30 minutes of sun exposure each day or take a supplement to get the recommended daily intake of 600 IU (15 mcg).

If your local weather looks like an endlessly gray “Twin Peaks” highway scene, then you prob aren’t getting enough vitamin D from the sun. According to research from 2013, folks who live far north or south of the equator often do not produce enough vitamin D from sunlight.

As a result, an estimated 50 percent of the global population is low in vitamin D. And some groups are at higher risk of vitamin D deficiency, such as:

  • older adults
  • breastfeeding infants
  • folks with darker skin tones
  • those who don’t get enough sun
  • people with obesity

Dated research from 2003 and 2004 suggests that a higher body mass index (BMI) and body fat percentage are associated with lower blood levels of vitamin D.

One theory is that folks with obesity might eat fewer vitamin D-rich foods, but there isn’t much research to support that link.

Other possibilities are that obesity exposes less skin to the sun and that folks with obesity spend less time outdoors — but again, there doesn’t seem to be any supporting research.

Your body also needs certain enzymes to convert vitamin D into its active form. And, according to a 2013 research article, levels of these enzymes tend to be lower in people with obesity. Still, we need more research to find out more about this link.

The amount of vitamin D your body needs may be connected to your weight.

A 2012 study found that if people with obesity were theoretically at their body’s “ideal” BMI, then they would be getting enough vitamin D for their body size.

In another 2012 study of women who were overweight or had obesity, those who lost weight had an increase in their vitamin D levels.

A large 2016 review echoed this finding, with researchers concluding that weight and fat loss seem to increase the vitamin D levels of people who used to have obesity.

Studies also suggest that vitamin D levels climb higher as people lose more weight. In a 2011 study, researchers found that people who lost 15 percent or more of their body weight experienced vitamin D increases 3 times greater than those who lost 5 to 10 percent of their body weight.

On the other hand, a 2014 study suggests that boosting vitamin D levels in the blood might help reduce body fat and encourage weight loss. So this may be a bit of a chicken-or-egg situation.

tl;dr on obesity, weight, and vitamin D

Obesity seems to be a risk factor for vitamin D deficiency. This is likely because your daily requirement for vitamin D depends on your body size. But since vitamin D also seems to aid in weight loss, there could be something more there.

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So now we know that weight loss = higher vitamin D levels. In true mathematical fashion, it seems the reverse is also true. Here’s the research breakdown:

  • In a 2018 study, researchers found that women who were overweight or had obesity experienced reductions in weight, BMI, waist circumference, and hip circumference after taking vitamin D supplements for 6 weeks.
  • In a 2014 study, women with obesity ate a calorie-restricted diet and exercised for 1 year. Half received a vitamin D supplement, and the other half got a placebo. Those who got enough vitamin D lost more weight — an average of 7 pounds more than the women who didn’t have sufficient vitamin D in their blood.
  • In a study from 2012, women who were overweight or had obesity took vitamin D supplements for 12 weeks. By the end of the study, the women had not lost weight, but their body fat had decreased. So, even if higher vitamin D levels don’t lead to weight loss, they might lead to fat loss.
  • Taking vitamin D could also help keep the pounds off. In a 2012 study of 4,600 women ages 65 and older, researchers found that higher levels of vitamin D were linked with less weight gain over 4.5 years.

Some research from 2008 notes that vitamin D could potentially suppress the formation of new fat cells in the body. Additional 2016 research supports this finding, showing that vitamin D also seems to suppress the storage of fat cells, which basically makes it hard for fat to form in your body in the first place.

Vitamin D also boosts levels of serotonin (the “feel-good hormone”), which might play a part in appetite control and increase feelings of fullness after eating. Naturally, this could decrease your calorie intake and, likewise, your body weight.

tl;dr on taking vitamin D to lose weight

Increasing your vitamin D levels *might* promote weight loss if you’re not already getting enough, especially if you also exercise and eat a nutritious diet.

Vitamin D might make it harder for fat to form and be stored in your body. It may also increase your levels of serotonin, which can help you feel more full after eating and may help with weight management.

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According to the National Institutes of Health, adults need at least 600 IU (15 mcg) of vitamin D each day.

Still, it’s not exactly a one-size-fits-all situation, since a decent amount of research suggests the ideal dosage should be based on body weight.

Researchers in a 2012 study adjusted vitamin D levels for body size, calculating that 32 to 36 IU per pound (70 to 80 IU per kilogram) is needed to maintain adequate blood levels.

So, depending on your body weight, this level could be much higher than the current standard upper limit of 4,000 IU per day. Doses of up to 10,000 IU have also been reported without any observed negative effects.

Keep in mind that vitamin D can still cause toxicity when consumed in large amounts, so it’s a good idea to talk with a healthcare professional before taking more than the upper limit of 4,000 IU per day.

Psssst: Check out our Greatist vitamin D supplement picks, from gummies to softgels, and even vegan vitamin D options!

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Need more big D energy in your life? Here’s how to get it.


Some of the top vitamin D foods to fill up on are:

  • Seafood. Rainbow trout, wild coho salmon, and halibut are especially D-lish picks.
  • Egg yolks. Research from 2018 suggests that hens raised on a pasture with lots of sun exposure lay eggs with much higher vitamin D levels than hens kept inside, so cage-free eggs might have up to twice as much vitamin D in some cases. Organic eggs may also have higher levels.
  • Some mushrooms. Commercially grown mushrooms usually don’t have much vitamin D since they’re grown in the dark. But research suggests that wild mushrooms like chanterelles, as well as any mushrooms that have been exposed to UV light, are good sources.
  • Fortified foods. Dairy and plant-based milks, cereals, and granolas are some foods that may be fortified with vitamin D.
  • Organ meats. Beef liver and pork liver have a decent amount of vitamin D. Most other meats don’t contain much of this vitamin.

Sunlight or sun lamps

Venturing into the sun requires a delicate balance of getting enough vitamin D to feel amazing but not getting burnt to a crisp (or otherwise harming your skin). Don’t forget the SPF!

Some scientists recommend exposing about one-third of your skin to the sunlight for optimal absorption — so maybe some pants and a tank? According to the recommendation, getting 10 to 30 mins 3 times a week during the summer should be enough for most people with lighter skin.

Since a lot of people with darker skin tones need more vitamin D, they may need more time in the sun.

If you live in a cloudy place, a sun lamp can also do the trick.

There’s def a correlation between vitamin D levels and weight. Though experts don’t know for sure what’s at work, people with obesity are more likely to have lower levels of vitamin D. Meanwhile, those who increase their vitamin D levels seem to be more likely to lose fat and weight.

You can get your fill of vitamin D with foods, sunlight, and — if necessary — supplements. When in doubt, talk with a healthcare pro about what’s right for you.