Sunbathing my back for 10 days made me lose 4 catties. Can sunbathing your back during the dog days really help you lose weight? The truth is →

"Sunbathing your back more during the dog days can help you lose weight!"

Recently, a netizen posted that he lost 4 catties after sunbathing his back on the roof for 10 days, and said that after sunbathing for half an hour every day, he felt that his eyes became clearer. Subsequently, the entry "Sunbathing your back for 10 days to lose 4 catties" became a hot search and a hot topic.

Rumor Analysis

That is not the case.

This is an isolated case, and weight loss may be related to multiple factors, including water loss and transient metabolic changes, but it does not mean a direct reduction in fat.

Recently, as we enter the dog days of summer, there has been a "back sunning" craze on social media platforms. Can sunning your back really help you lose weight? What are the benefits of sunning your back to our bodies? What are the harms of sunning your back if you do it incorrectly?

Can sunbathing your back really help you lose weight?

We all know that losing weight requires creating an energy gap, and the body will consume its own fat to fill this gap, thereby achieving the goal of weight loss/fat reduction.

Generally speaking, 1g of fat can release 9kcal of energy. This netizen wants to lose an extra 4 kilograms, which is equivalent to creating an energy gap of 4 kilograms outside of the basal metabolism for the body to consume.

Losing 4 catties of fat is equivalent to burning 18,000 kcal of energy, which means releasing 1,800 kcal of energy every day on average. If we compare this with the energy consumption of exercise, we will know how large this number is.

Studies show that non-overweight women consume an average of about 567.6 kcal per day, while overweight or obese women consume 405.9 kcal. If this netizen really lost 4 kilograms of fat by sunbathing her back, it means that her body consumes three to four times the energy of moderate to high-intensity physical activities every day, which is obviously unrealistic.

Therefore, sunbathing to lose weight is not scientific, and short-term weight changes may be more dependent on water loss rather than fat burning. There are several possible explanations for this netizen's weight change:

1. Because of the sun and high temperature, my appetite decreased. I couldn’t eat in the past few days, so I lost weight.

2. Sun exposure causes dehydration in the body, and these weight changes are actually due to water loss.

3. For some people, normal weight fluctuations are within a few kilograms, which may be just normal fluctuations.

However, sunbathing is not without benefits. Instead, there are risks and benefits . We must understand the issue of sunbathing scientifically and rationally.

Sunbathing does have benefits

Appropriate sun exposure can bring benefits to the human body. The most widely known is that it can support the body's production of vitamin D, which can better absorb calcium , and vitamin D may also be a protective factor for other diseases.

Studies have found that the body only needs to be exposed to sunlight for 3 to 15 minutes at noon each day to meet its vitamin D needs (exposure time can be slightly longer at other times), and good sun protection is needed to avoid damage to the skin.

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In addition, sunlight may really affect fat . Studies have found that blue light in sunlight can activate the ion channels of fat cells, thereby activating the signaling pathways that regulate lipid metabolism in fat cells and starting lipid decomposition.

This study cannot be used as a basis for weight loss . It more shows that " sunlight helps maintain normal fat metabolism in the body " because the more sunlight you get, the more fat you metabolize. It's just that our human body needs a certain amount of sunlight to function normally. Therefore, it cannot be regarded as helping to lose weight, but it can reduce the risk of metabolism-related diseases.

The role of moderate sunlight in maintaining normal human function is not only reflected in the operation of fat cells, but also in maintaining cardiovascular function, blood sugar metabolism and other human functions. It can reduce the risks of high blood pressure, diabetes, etc., but it cannot be considered a treatment method.

Pay attention to these when sunbathing

At the same time, the risks and side effects of sun exposure cannot be ignored. Excessive exposure to the sun may cause a series of health problems.

For those who love beauty, sun exposure may also accelerate skin aging . Ultraviolet rays can destroy the collagen and elastic fibers in the skin, causing the skin to lose elasticity, develop wrinkles and spots, and may also cause skin burns.

In addition, skin cancer has always been the main disease risk after exposure to ultraviolet rays. Sun exposure and sunbathing are the main sources of ultraviolet radiation. High ultraviolet radiation is estimated to increase the risk of malignant melanoma of the skin by up to 2 times; and this risk is higher for people with fair skin. At present, there is no widely accepted evidence that sunscreen can reduce the risk of this cancer.

High temperature exposure can also cause dehydration . If you expose your back to the sun for a long time, your body will sweat a lot. If you don't replenish water in time, you will become dehydrated, and in severe cases, you may even suffer from heat stroke.

For health and safety, we still need to pay attention to the appropriate time for sun exposure, not too short or too long. Studies have found that the optimal time for outdoor sunlight exposure is an average of 1.5 hours per day .

How to lose weight scientifically

If we want to lose weight, we should choose scientific and reasonable ways to lose weight, and avoid neglecting the overall health of the body in pursuit of rapid weight loss.

First of all, a proper diet is the basis of healthy weight loss. We should balance the nutritional intake in our diet, eat more fiber-rich vegetables, fruits and whole grains, and reduce the intake of high-sugar, high-fat and high-calorie foods. The right amount of protein and healthy fats are also very important for the body. Formulating a healthy diet plan and strictly following it is the key to achieving healthy weight loss.

Secondly, regular exercise is essential. Doing at least 150 minutes of moderate-intensity aerobic exercise per week, such as brisk walking, running, swimming, etc., can help increase metabolism and burn excess fat. At the same time, proper strength training can also increase muscle mass and promote the increase of basal metabolic rate. Exercise not only helps to lose weight, but also improves cardiopulmonary function and mental health.

Furthermore, it is also very important to maintain a good lifestyle . Sufficient sleep and low stress levels are also helpful for weight loss. Studies have shown that lack of sleep and excessive stress can lead to weight gain, so ensuring 7 to 8 hours of high-quality sleep every day, as well as taking measures to relax and reduce stress, are very beneficial for healthy weight loss.

In addition, set realistic weight loss goals and stick to them . Losing weight is a long-term process and you should not rush for success. Setting small goals and achieving them step by step can help you maintain motivation and confidence. Recording your daily diet and exercise is also an effective way to maintain self-discipline.

Finally, it is worth considering seeking professional help . If you find it difficult to control your weight on your own, consulting a nutritionist or professional doctor to develop a personalized weight loss plan can provide more guidance and support.

In short, healthy weight loss requires a comprehensive consideration of diet, exercise, lifestyle and mental state. Only scientific and reasonable adjustments can truly achieve the effect of weight loss while maintaining physical health and vitality.

Looking in the mirror of rumors

This rumor ignores individual differences, such as health conditions, and the effects of sunbathing on different people may be very different. Moreover, such rumors often tend to exaggerate the effects of sunbathing, but they have not been scientifically verified, and the lack of specific suggestions also increases the unreliability of the information.

For healthy weight loss, we should still follow scientific diet and exercise methods and consult professional nutritionists or doctors.

Author: Jiang Yongyuan, Master of Internal Medicine, Third Military Medical University

Reviewer: Tang Qin, Director of the Science Popularization Department of the Chinese Medical Association, National Health Science Popularization Expert