Scientists Uncover a Surprising Connection Between Appetite and Sun Exposure

Fat Man Eating Fast Food

The study found that sun exposure activates a protein that stimulates the appetite.

Visiting the beach? Going on a hike? Be ready: Men will be hungrier!

According to recent research from Tel Aviv University, exposure to the sun makes men more hungry but not women. The research, which was conducted using lab models, reveals how the metabolic mechanism is activated differently in men and women. According to the researchers, sun exposure in males of both animal species and humans triggers a protein called p53 to repair any DNA damage that may have been done to the skin as a result of the exposure.

Carmit Levy

Professor Carmit Levy. Credit: Tel Aviv University

Ghrelin, a hormone that increases hunger, is produced by the body in response to the activation of p53. The hormone estrogen prevents the interaction of p53 with ghrelin in females, which prevents the urge to eat after exposure to the sun.

Professor Carmit Levy and Ph.D. student Shivang Parikh of the Department of Human Genetics and Biochemistry at TAU’s Sackler Faculty of Medicine led the groundbreaking study.  It was carried out in partnership with numerous Israeli and international researchers, including Tel Aviv Sourasky (Ichilov), Assuta, Meir, and Sheba Medical Centers, as well as Dr. Yiftach Gepner and Dr. Lior Bikovski from TAU’s Sackler Faculty of Medicine and Professor Aron Weller from Bar-Ilan University. The study was published in the renowned journal Nature Metabolism.

The study’s epidemiological data, which included self-reports from students who had spent time in the sun, were gathered over the course of a yearlong survey of about 3,000 Israelis of both sexes about their eating habits. This data was combined with the findings of a genetic study performed in a lab model. The results show that both in laboratory models and in people, the skin is a key regulator of energy and appetite (metabolism).

The researchers explain that there is a dramatic metabolic difference between men and women, impacting both their health and their behavior. However, so far it has not been established whether the two genders respond differently to environmental triggers such as exposures to the sun’s UV radiation.

Professor Levy: “We examined the differences between men and women after sun exposure and found that men eat more than women because their appetite has increased. Our study was the first gender-dependent medical study ever conducted on UV exposure, and for the first time, the molecular connection between UV exposure and appetite was deciphered. Gender-dependent medical studies are particularly complex since twice the number of participants are required in order to find statistically significant differences.”

Professor Levy concludes: “As humans, we have cast off our furand consequently, our skin, the largest organ in our body, is exposed to signals from the environment. The protein p53, found in the skin, repairs damage to the DNA caused by sun exposure, but it does more than that. It signals to our bodies that winter is over, and we are out in the sun, possibly in preparation for the mating season. Our results provide an encouraging basis for more research, on both human metabolism and potential UV-based therapies for metabolic diseases and appetite disorders.”

Reference: “Food-seeking behavior is triggered by skin ultraviolet exposure in males” by Shivang Parikh, Roma Parikh, Keren Michael, Lior Bikovski, Georgina Barnabas, Mariya Mardamshina, Rina Hemi, Paulee Manich, Nir Goldstein, Hagar Malcov-Brog, Tom Ben-Dov, Ohad Glaich, Daphna Liber, Yael Bornstein, Koral Goltseker, Roy Ben-Bezalel, Mor Pavlovsky, Tamar Golan, Liron Spitzer, Hagit Matz, Pinchas Gonen, Ruth Percik, Lior Leibou, Tomer Perluk, Gil Ast, Jacob Frand, Ronen Brenner, Tamar Ziv, Mehdi Khaled, Shamgar Ben-Eliyahu, Segev Barak, Orit Karnieli-Miller, Eran Levin, Yftach Gepner, Ram Weiss, Paul Pfluger, Aron Weller and Carmit Levy, 11 July 2022, Nature Metabolism.
DOI: 10.1038/s42255-022-00587-9

36 Comments on "Scientists Uncover a Surprising Connection Between Appetite and Sun Exposure"

  1. I am male, 90 years old. i eat less in hot weather.

  2. This is 100% FALSE

  3. The university I attend, tested this with 1000 people. They have determined this is 100% misleading and not the answers we got. It’s crazy how some fools will believe anything as long as it comes from someone in a lab coat.

  4. They keep deleting my comments! This is illegal to do in my country. You are spreading false information.

  5. Food is food, sun or not.

  6. I have porphyria with an extreme sensitivity to the sun. 38/f. While the go to treatment for an acute porphyria attack is indeed carbs/glucose loading so I am unsure of the relevance to this article, bearing my porphyria diagnosis, but I become absolutely ravenous after sun exposure. I am in a constant state of hypoglycemia (60 after sun exposure) with my blood sugar never rising above 98 after a full carb and sugar meal, I could eat cake, toast, juice, milk and cereal and my sugar never rises above 98. Worth a mention, hoping science will figure it out. Maybe this is a better explanation for the change in men after sun exposure.

  7. It didn’t say eat more in hot weather, it says the UV from the sun triggers hunger in men.

  8. Andre Williams, I mean no offense, but at 90 years old you may be hormonally very different from the other men in the study

  9. To Andre Williams, perhaps it is because your mate-seeking behavior had significantly declined due to age. The reproductive imperative would be most urgent and strongest in younger males.

  10. What about menopausal women? I would think, had they checked young & menopausal women this would have strengthened their conclusion about estrogen.

  11. Interesting, but myself (female but with PCOS so my hormones are abnormal), my brother, and my father find that we have less appetite in hot weather. I get nauseous at anything higher than 30c, especially in direct sun. We live in Canada where summers are rarely extreme and tend to be short… I wonder if it’s got to do with acclimatization or genetics?

  12. I believe this is true. I spend at least 30 minutes a day in direct sunlight in Texas heat. I feel the sun rays stinging my skin. And I have hunger pangs after returning inside even if I ate a big meal 3 hours before. I think people saying this is false aren’t really in the sun like that like I am. I’m talking I’m 2 shades lighter in the winter.

  13. I work all day every day in the sun and it destroys my appetite. I don’t even think about food. Your lab model research is pointless. You could have just went outside and asked some people actually working.

  14. When I’m in Canada I eat alot more because the weather is very depressing for me. When I am in a sunny country like Greece or Portugal I usually eat once a day:)

  15. I wonder if that includes the different levels of physical activity between the male and female subjects

  16. That isn’t true actually. My Husband spent his whole life in the Military, Outside, consuming 3000 Calories per MRE Meal…and NEVER gained weight..he is STILL trim in his late 50’s, is always Outside and eats WHATEVER he wants, DRNKS whatever he wants (though usually never stops to eat when he is working), LOVES Starbucks Frappuccinos. So…as pet usual this is not the case for everyone. I eat sensibly excercise constantly and can’t keep the weight off. 😫

  17. This is lies! I’m a male work any where between 10-18 hours in direct sunlight and heat of Florida. Not only does the sun make me not want to eat at all and the thought turns my stomach.but also what species are they talking about they list 3 types, but only say “both species and humans” now never knew there were only 3 species in the world 1 being human, and they never list the 2nd and 3rd type. Are they trying to say there are 3 types of humans species, male, female, other? Imo this writer is garbage, the company they work for is garbage, and this article is garbage we read news to be informed not to be told stories by idiots that havnt actually did any research. This is all lies.

  18. Food for thought: they are claiming a statistical difference between the sexes, which is not a claim about every individual within the population. For example, men are statistically larger than women. This does not mean that every man is larger than every woman. Your anecdotal evidence about a single person is not sufficient evidence to discredit the claim at the population level. Now, whether the claim holds remains to be seen — additional testing would be required either way.

  19. From my observations as a woman from a semi-desert city,in a sub Saharan country near the equator. Where we probably get as much sun and UV rays as physicaly possible, and excuse my French but this is some bs most men here a less overweight compared to the women which is supposed to be the opposite according to this study.

  20. As a woman over 60 years I tend to be less hungry when I’m too hot and it seems to be more so if I’ve gone out in the sun that day vs at home all day but overall I don’t feel very hungry if my body’s too hot.

  21. It would be nice if people that commented on an article had the mental capacity to understand what was written in the article

  22. I also wonder if being post menopsusal makesveomen hungry in the heat. And if maybe some of that is due to mistaking dehydration for hunger. Would be nice to read an answer.

  23. Not true at all. I’m a woman of 28 and I’ve always been way more hungry in the summer than in the winter.

  24. 38yrs old male I find this hard to believe I have lived in tampa florida for 5yrs and work10 hour days doing bridge work as a form carpenter and if I would eat something I would be nauseous, so for me not happening

  25. What is a woman?

  26. These people are anti-trans.

  27. For white men what about black men

  28. Laurence McGill | September 5, 2022 at 9:59 am | Reply

    Anyone else sungry?

  29. So, if a man identifies as a woman, then “she” won’t have increased appetite? Of course she won’t. Lolol

  30. I am a Home Based Registered Dietitian who specializes in geriatric malnutrition. Just had a Home Visit last Fri and convinced patient who has not been out of house in a year to come sit on front porch in the fresh air and sun with me for visit. Registered Dietitians have often seen correlation between those with healthy appetite and those that spend time out in the fresh air and sun. The outdoors is healing.

  31. It seems like many of the commenters are associating these findings with heat and hunger, not sunlight and hunger. Yes, it can be hot in the sun, it can also be freezing cold in the sun.

  32. I’m 50 I work in the sun all day I don’t get hungry

  33. After reading the comment section, yes, exactly what I expected.

    Idiots not understanding simple statistical analysis; idiots screaming they are outliers; idiots screaming about there being only two genders.

    Idiocracy was prophetic.

  34. Scienceguy isn’t a real person, just a robot with a vagina. This country is free the way it outta be, so take your socialist, fascist, or communist agendas and shove ’em up your commy-pink robo-snatch-hatch!

  35. When I’m in the sun I’m usually highly active. Running, swimming, tennis, chick’s on the beach, etc. Sure, I’m hungry, but I love crisp salad, chilled fruit, grilled fish or chicken. Fall/winter I’m eating more calories like stews, potatoes, roast, etc. Can’t speak for women though. Women I’ve been with eat hearty as well.

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