Sitting in the sun has long been touted as a way to help lose weight. The idea is that by exposing your body to sunlight, you can increase vitamin D levels, regulate hormones, boost metabolism, and burn more fat. But is there any truth to this? Can simply basking in the sun really help you shed pounds? Here is a quick look at the evidence.
How does sun exposure affect weight?
There are a few ways that sitting in the sun may potentially aid weight loss:
- Increases vitamin D levels. Low vitamin D is linked to obesity. Sun exposure boosts vitamin D, which may help regulate weight.
- Regulates hormones. Sunlight exposure regulates levels of leptin and adiponectin, hormones involved in hunger/fullness cues.
- Boosts metabolism. Some research shows sun exposure raises resting metabolic rate, increasing daily calorie burn.
- Burns calories. Simply sitting in the sun burns calories as your body works to cool itself.
So in theory, getting more sun could support weight loss through these mechanisms. But what does the research say?
What research says on sun exposure and weight loss
There have been several studies examining the relationship between sun exposure and weight:
- A 2014 study followed over 4,000 women aged 20-85 years old. Those who had higher sun exposure had a lower risk of obesity over the 4-year study.
- Another study in over 400 overweight adults found that those randomized to increase sun exposure lost more weight over a 6-week period, compared to no sun exposure.
- One small study in 36 women found sunbathing significantly reduced appetite hormones leptin and ghrelin.
- However, not all studies have found a benefit. One study in overweight adults found no difference in Vitamin D levels or weight with increased sunlight.
Overall, some research does suggest a link between sun exposure and modest weight/fat loss. However, more studies are still needed.
How much sun is needed to lose weight?
There are no specific recommendations for how much sun is needed to burn fat or lose weight. However, most research showing benefits have involved fairly brief full-body sun exposure:
- 10-30 minutes of midday sun exposure in a bathing suit 2-3 times per week.
- At least 15-30 minutes of sun 2-5 times per week, exposing at least 40% of skin area.
Again, more research is still needed to determine optimal sun exposure for weight loss. It’s possible even smaller amounts could have an effect.
Other benefits of sun exposure
In addition to potential weight loss effects, getting regular sunlight has a number of other health benefits:
- Vitamin D production: Sun exposure is the best way to get vitamin D, which regulates calcium absorption for bone health and has many other roles.
- Improved sleep: Sunlight regulates your circadian rhythm, helping maintain healthy sleep-wake cycles.
- Better mood: Sunlight exposure releases serotonin, acting as a natural mood lifter to reduce risk of depression and seasonal affective disorder.
- May reduce risk of certain cancers: Some research shows sun exposure could lower risk of several cancers including breast, colon, ovarian, and prostate cancer.
Of course, excessive sunlight and sunburns should always be avoided given the increased risk of skin cancer. But modest regular sun exposure offers many health perks beyond just potential weight loss.
Maximizing weight loss from sun exposure
If you’re going to spend time tanning with weight loss in mind, here are some tips to maximize potential benefits:
- Expose lots of skin: Don’t just sit with a small fraction of skin exposed. Wear swimsuits or shorts and tank tops to expose as much skin as possible to maximize vitamin D and leptin/ghrelin regulation.
- Hit midday sun: The sun’s rays are strongest midday between 10am-3pm. Plan your tanning sessions during peak daylight hours.
- Do it regularly: Don’t just tan once a month. Aim for at least 2-5 sessions per week for best results.
- Stay hydrated: Drink plenty of extra fluids before and after to avoid dehydration.
- Don’t burn: Build up sun exposure gradually if you’re very pale to avoid burning. Too much sun exposure and burning could increase skin cancer risk.
Maximizing skin exposure during peak midday hours several times per week provides the best shot at utilizing sun’s potential weight loss effects.
Risks of excessive tanning
While moderate sun exposure offers many benefits, excessive tanning and sunburns come with many potential risks:
- Skin cancer: Excessive UV radiation is the #1 risk factor for melanoma and other skin cancers.
- Photoaging: Too much sun exposure leads to wrinkles, age spots, and other premature skin aging.
- Burns: Sunburns damage the skin and can be quite painful.
- Heat illness: Sitting in the sun too long can lead to heat rash, heat cramps, or heat stroke.
- Eye damage: UV rays can burn the cornea and retina, raising chances of cataracts.
To minimize risk, avoid sun bathing midday, always wear UV-blocking sunglasses, and use sunscreen. Getting vitamin D from food sources like fish or supplements can also minimize sun exposure needed.
The bottom line
Here is a quick summary on whether sitting in the sun can help promote weight loss:
- Some research shows a link between sun exposure and lower body weight/fat.
- Sunlight may contribute to fat burning by regulating hormones, boosting vitamin D, and raising metabolism.
- Short sessions of midday sun exposure exposing large skin area may maximize benefits.
- But excessive tanning and sun burns come with skin cancer risks, so moderation is key.
- More large scale studies are still needed to make definitive conclusions on sunlight and weight loss.
While sitting in the sun shows some promise for potentially aiding weight loss, it should not replace traditional methods of diet and exercise. Instead look at time outdoors as a complementary tool that may provide additional metabolic benefits when practiced safely and in moderation.
Frequently Asked Questions
How does vitamin D help with weight loss?
Vitamin D from sun exposure could potentially promote weight loss in a few ways:
- Corrects vitamin D deficiencies, which are linked to obesity.
- May improve insulin sensitivity and blood sugar control.
- Boosts levels of adiponectin, a hormone involved in fat burning.
- Reduces parathyroid hormone, which can stimulate fat formation.
- May suppress development of new fat cells by regulating gene expression.
Overall, maintaining adequate vitamin D appears beneficial for metabolism and weight management.
What time of day is best for tanning to lose weight?
The best time of day to tan for weight loss is typically between 10am-3pm, when UV exposure is most intense. This midday window allows your body to produce the most vitamin D and has been shown in research to be most effective for fat burning and hormone regulation.
Does tanning help burn more calories?
Yes, there is evidence that simply sitting in the sun does burn additional calories as your body expends energy trying to cool itself. In one study, resting energy expenditure increased by over 100 calories per hour of sunbathing. So tanning can create a mild calorie deficit to support weight loss over time.
Can you lose weight by sunbathing indoors?
Most research on sun exposure for weight loss has involved natural outdoor sunlight. There isn’t much evidence that indoor tanning beds have the same metabolic benefits. They don’t allow vitamin D production and may not replicate the same hormone regulation effects.
Are there risks of sun exposure without sunscreen?
Yes, excessive sun exposure without sunscreen raises your risk of sunburns, skin cancer, premature aging, and eye damage. It’s important to gradually build up natural sun exposure and use sunscreen to avoid overdoing it. The risks of too much sun outweigh any potential weight loss benefits.
Conclusion
Some scientific research indicates that safe, moderate sun exposure could potentially play a role in a weight management strategy. Sitting in the midday sun may help burn calories, improve vitamin D status, regulate fat-burning hormones, and raise metabolism. However, excessive sunlight and burning carries significant health risks. More research is still needed to make conclusive recommendations on sun exposure protocols for weight loss. For now, natural sunlight in moderation can be considered a supplemental tool, but not a replacement for diet and exercise. Consult your doctor before significantly increasing unprotected sun exposure for the sake of potential weight loss.
