Does tanning burn fat? Yes and no.
Being in sunlight has many benefits and can boost your metabolic rate, and well-being and even help with fat loss.
Read to the end to find out the ideal protocol for how to lose fat when tanning.
UV light explained
For thousands of years, humans have understood that sunlight has an important and significant impact on human health and disease.
Sunlight is composed of three major wavelength bands: visible light (wavelengths of 400–800 nm); UVR (wavelength of 100–400 nm); and, infrared radiation (wavelengths > 800 nm). The wavelengths of UVR are further divided into three main categories: UVA (315–400 nm), UVB (280–315 nm) and UVC (100–280 nm).
UVA and UVB comprise 95% and 5% of UV rays that reach the Earth’s surface. UVC is prevented from reaching the Earth’s surface by the ozone layer.
The amount of solar UVR that reaches the terrestrial surface at any given place and time is influenced by a variety of factors including; time of day, season, geographic latitude, altitude, cloud cover and surface type.
Although we need adequate amounts of UVB to create vitamin D, we also benefit significantly from UVA and other light spectrums of sunlight.
Why tan for fat loss?
Sunlight has a host of benefits, which include a faster metabolism, which leads to lower fat mass.
Studies have shown that there are seasonal increases in adiposity, BMI, abdominal obesity and HbA1c levels during the winter months (R).
In rats, UV light exposure can significantly limit diet-induced obesity (R).
According to surveys, the primary motivation to tan is the desire to look attractive and appear healthy to their peers (R). Other reasons include the desire to develop a “protective base tan” prior to prolonged sun exposure, self-treatment of various skin conditions such as acne, and a desire to increase vitamin D levels.
Additionally, those who use tanning beds report a feeling of relaxation and a sense of physical and mental well-being after tanning (R). There are a couple of reasons for this which we’ll get into in a bit, but the main reason is the release of endorphins. Some people literally get addicted to sunlight.
7 ways how sunlight-induced tanning helps burn fat
#1 Sunlight reduces appetite
There are 4 main ways that sunlight can help to reduce appetite.
- Sunlight boosts dopamine. Dopaminergic drugs (e.g. Ritalin) suppress appetite. Significant weight loss is often a side effect of dopaminergic drugs. Sunlight will not nearly be as potent as drugs, but it can still significantly reduce appetite
- Sunlight boosts serotonin. Serotonergic drugs are frequently prescribed for obesity since it reduces appetite. However, it has many side effects as well. Sunlight doesn’t have the same side effects as serotonergic drugs, but only upsides.
- Sunlight helps regulate the body’s circadian rhythm. The circadian rhythm (our internal clock) controls our sleep and wake cycles as well as appetite and much more. If our internal clock is off due to stress, sleep loss, night shift, etc, this can lead to food cravings and excess caloric intake and eventually weight gain.
- UV exposure boosts α-MSH production. α-MSH may help prevent obesity by suppressing appetite and speeding up the metabolic rate (R).
I don’t know about you, but when I’m outside a lot on a hot day, I don’t have much of an appetite. Long cold days inside jack up my appetite quickly.
#2 Sunlight increases energy levels
Sunlight exposure increases dopamine, serotonin, T3 (active thyroid hormone) and POMC, all of which boost energy and elevates mood.
Testosterone has been shown to boost physical activity specifically by binding to the androgen receptor, which then promotes the release of dopamine (R).
POMC is a peptide released from the pituitary and it’s the precursor to melanocyte-stimulating hormone (α-MSH) and adrenocorticotropin hormone (ACTH). Both of which boost energy levels.
Lastly, low vitamin D levels have been linked to fatigue and low energy levels. However, it’s likely not specifically low vitamin D that’s the culprit, but rather a lack of sunlight exposure.
#3 Sunlight increases testosterone
Testosterone is inversely correlated with fat mass. Meaning, men with high testosterone are often leaner than those with low testosterone.
A 2013 study found that 32% of men around 45 years of age and 75% of men with severe obesity (BMI > 40 kg/m2) had hypogonadism (R). The largest study evaluating hypogonadism in 2162 males 45 years and older reported that 38.7% were hypogonadal (R, R).
There is this catch-22. Obesity lowers testosterone and low testosterone causes weight gain.
As you can see from the table above, people with a lower BMI (<25) tend to have testosterone over 521ng/dl. It’s still not high, but at least not hypogonadal. If they ate more animal foods and implemented testosterone optimization strategies, their T will likely be >700ng/dl, which is commonly what I achieve with my clients in a couple of weeks.
Testosterone replacement therapy (TRT) also promotes weight loss in most individuals.
Testosterone also promotes the activity of the thyroid gland and enhances dopamine release. More on why those are important later.
Testosterone helps you stay lean by:
- Reducing excess appetite
- Improving insulin sensitivity
- Increasing energy
- Improving sleep
- Enhancing muscle mass, which increases the metabolic rate.
- Increasing the metabolic rate. Testosterone promotes mitochondrial production and speeds up mitochondrial function as well.
- Lowering cortisol. Cortisol promotes fat storage, particularly in the abdominal area. Lower cortisol levels can help reduce belly fat.
#4 Sunlight increases dopamine
Dopamine and its metabolite, noradrenaline, promote energy expenditure. Noradrenaline works in synergy with the thyroid hormone T3 to speed up the metabolic rate.
Dopamine and noradrenaline have anti-depressant effects and make you want to do things. The desire to do things leads to higher daily energy expenditure. Being more active helps to promote fat loss.
Sunlight has been shown to increase both dopamine and T3, and this will lead to greater energy expenditure and fat loss.
#5 Sunlight increases thyroid hormones
UV light exposure has been shown to increase thyroid gland activity and increase T4 (R). T4 is the precursor hormone to the active thyroid hormone, T3.
Longer, warmer days increase the conversion of T4 into T3.
T3 speeds up the metabolic rate. Low levels of T3 (subclinical hypothyroidism) slow the metabolic rate and promote weight gain.
Hyperthyroid individuals are almost always very lean with very little body fat, whereas hypothyroid individuals are often overweight (or struggle to lose fat).
#6 Sunlight increases nitric oxide release
Skin exposure to UV light triggers the release of nitric oxide into the bloodstream.
This improves vasodilation. More blood flow to fat cells can help boost fat loss.
Additionally, animal studies have shown that dietary nitrate (which converts to nitric oxide) causes the browning of white fat cells. Browning means that white fat cells are converted to mitochondria-rich brown fat cells. These mitochondria don’t produce much energy, but “waste” the fat into heat. This is called thermogenesis and it has potent anti-obesogenic effects (R).
#7 UV light shrinks fat cells
A 2017 study found that white fat cells are light-sensitive. Almost as if they had a light “receptor”.
“This pathway is activated at physiological intensities of light that penetrate the skin on a sunny day. Daily exposure of differentiated adipocytes to blue light resulted in decreased lipid droplet size, increased basal lipolytic rate and alterations in adiponectin and leptin secretion.” (R)
UV light has also been shown to inhibit the synthesis of new fat in fat cells, thus preventing the expansion of existing fat cells (R).
In summary, sunlight inhibits fat synthesis, decreases fat droplet size and increases lipolysis, which mobilizes fat out of the fat cells.
In theory, sunlight does shrink fat cells.
Why supplementing vitamin D won’t help with fat loss
When human skin is exposed to UVB radiation, vitamin D3 is produced from cholesterol in the skin.
Lower circulating levels of vitamin D have been associated with obesity, fatty liver, insulin resistance, metabolic syndrome, type-2 diabetes and cardiovascular disease (R).
Vitamin D has also been shown to inhibit the growth of new fat cells (R). Less fat cells = less fat gain.
However, meta-analyses of clinical trials have shown that vitamin D supplementation doesn’t help with weight loss, coronary artery disease or hypertension, or reducing signs of cardiometabolic risk such as glucose tolerance, insulin sensitivity or circulating lipids (R).
In this case, it’s because the association is not causation. The cause is a lack of sunlight exposure.
Side effects of sunlight
The only two side effects of sunlight are burning and heat shock. Burning is a result of skin damage, oxidative stress, and inflammation.
For a long time, people have thought that sunlight causes skin cancer and should be avoided.
Sunlight doesn’t cause skin cancer of any kind. However, other factors, such as chronic burning, a high PUFA diet, already being in an inflamed state, or being exposed to environmental toxins, might increase the risk.
Here are a few quotes from a few studies. Abrev used: BCC (basal cell carcinoma) and SCC (squamous cell carcinoma).
“non-burning sun exposure is associated with a reduced risk of melanoma, while sunburns are associated with a doubling of the risk of melanoma.12 It has long been observed that outdoor workers have a lower incidence of melanoma than indoor workers.13-19” (R)
“Rosso et al. 199852 found no association between cumulative lifetime sun exposure and BCC….
Gallagher et al. 1995a,b54,55 found no association between cumulative lifetime sun exposure and risk of SCC or BCC…Alam et al. 200158 found that the risk of SCC, but not BCC, is directly related to cumulative total dose of ionizing radiation from x-rays, that SCC may develop on sun-exposed areas in people with certain genodermatoses, such as oculocutaneous albinism, that chemical agents such as soot, arsenic and polycyclic hydrocarbons have historically been a major cause of SCC, and that human papillomavirus infection has been associated with SCC. The US. Preventive Services Task Force, in its May 2012 Final Recommendation Statement on skin cancer counseling,59,60 stated that studies that measured long-term or total sun exposure had found no association between cumulative sun exposure and either SCC or BCC.” (R)
In summary, tanning doesn’t contribute to skin cancer. However, if your diet is suboptimal, it might lead to skin aging and other diseases.
Other benefits of sunlight/tanning
There are countless benefits to getting ample sunlight daily. Some of these benefits include:
- Lower LDL-cholesterol levels (R).
- Reduced blood concentrations of inflammatory markers (C-reactive protein and interleukin-6) (R).
- Prevention of the development of autoimmune conditions.
- Reduction in the risk of type-2 diabetes, thromboembolic events and all-cause mortality, independent of physical activity (R).
- Reduced incidence of cancers of the breast, prostate, colon/rectum and non-Hodgkin’s lymphoma (R).
- Greater cancer survival (R).
- The inverse association with some (but not all) infections, including tuberculosis and acute respiratory tract infections (R).
The ideal tanning protocol for burning fat
Sunlight by itself doesn’t promote fat loss. But it boosts so many other things that will improve energy and well-being, which will allow you to be more active.
Utilize this boost and do some form of activity when outside.
I personally walk the dogs for 30-40min daily without a shirt around 10 am each day. Later in the day, I jump trampoline for another 20-30min without a shirt in the sun.
This allows me to accumulate roughly an hour of activity each day, while reaping all the benefits of sunlight.
So instead of jumping on the treadmill or stationary bike, rather go outside and reap the benefits of sunlight.
Also, you don’t need to be without a shirt to reap the benefits of sunlight. Exposing your eyes and some skin to UV light will give you most of the benefits. I do recommend getting as much full upper body sunlight as you can when you can. People have told me that when they do that, that’s when they feel the best.
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Additional questions about tanning and fat loss you might have
How many calories does tanning burn?
Sunlight can boost the metabolic rate, but the fat loss benefits are going to be minuscule if you aren’t active as well.
Most people just lie in the sun when tanning, and lying still in the sun doesn’t burn any more calories compared to sleeping in the dark.
Can tanning make you lose weight?
Yes, tanning can help with fat loss, but only if you’re active as well. Sunlight will boost your desire to be active, so utilize it.
Do tanning beds burn belly fat?
Tanning beds contain UVA and UVB, depending on the bed, which might help with fat loss. UV light can boost nitric oxide, which promotes blood flow to the abdominal area as well as convert white fat to brown fat. However, to make the best of UV exposure, be sure to exercise afterward.
Does the sun speed up the metabolism?
Sunlight promotes the production of testosterone, T3, dopamine, noradrenaline, MSH and ACTH, all of which speed up the metabolic rate, increase energy expenditure and reduce appetite.
Is natural sunlight better for burning fat?
Yes, natural sunlight is broad-spectrum light, whereas tanning beds is only UVA and UVB. The reason why broad-spectrum light is better is that it also contains blue, red and near-infrared light that helps with fat loss.
You lose out on those benefits with a tanning bed.
Tanning for different skin types
People of all skin colors will get the same benefits from the sun. This is because most of the benefits aren’t via vitamin D synthesis.
Darker-skinned individuals need to spend more time in the sun to create vitamin D. But they will get the same boost in testosterone, dopamine, serotonin, etc, as light-skinned individuals, because it’s vitamin D independent.
Should you use sunscreen?
Sunscreen deflects or absorbs UV light, thus reducing the impact it has on the skin. Sunscreens with an SPF under 30 don’t seem to interfere with the synthesis of vitamin D, whereas high SPF sunscreens do.
Does sweating in the sun burn calories?
Sweating either in the sun or in a sauna doesn’t burn fat because it’s not induced by activity. Sweating is just a byproduct of the body overheating and wanting to cool off.