Dear Dr. Eva,

I like to get a tan and keep it through the summer. I’ve been doing this for years. I tan gradually and don’t let myself get burned. Do I need to worry about skin cancer?

Glowworm

 

Dear Glowworm,

Unfortunately, there is no safe tan. Although a gradually developed tan can protect some people from sunburn, tanning is caused by the same ultraviolet light frequencies which cause skin cancer, ultraviolet (UV) A and B. People who tend to tan rather than burn do have a lower baseline risk of skin cancer, but they increase their risk with each tan. The deeper the tan, the more the skin damage and the higher the cancer risk. Sun damage also causes premature wrinkles and aging, which are not wanted by most people who are concerned about their looks.

It’s time to change your view of what’s attractive and realize that a tan-induced glow is not healthy. Skin cancer rates have been rising very fast, with non-melanoma skin cancer rates increasing 77% between 1994 and 2014 due to damage to the protective ozone layer of the atmosphere. Between 2010 and 2020 in the US, new cases of invasive melanoma, the most deadly form of skin cancer, have increased by 47%

Ways to protect your skin from sun damage:

  • Avoid the sun between 10 am and 3 pm. Get out for some morning sun before 10 am, and enjoy the late afternoon sun, when the rays are less direct and less harmful. Midday stay indoors for a siesta.
  • Use sun block or sunscreen – there’s no difference medically between the two. Make sure it’s strong enough: use “high protection”, meaning a sun protection factor (SPF) of 15 or higher. If you will be swimming or are likely to be sweating, choose a water-resistant preparation.
  • Wear sunglasses to protect your eyes. Pick some good-looking ones, but make sure they are labeled as blocking 99% of UVA and UVB.
  • Wear a hat with at least a three-inch brim all the way around: a baseball type cap will not do the job. A hat plus sun block on the face are important to prevent cancer at the commonest sites: ears, nose, forehead, and the back of the neck.
  • Lightweight, light-colored long-sleeved clothes are a good idea, but you can burn through them if the weave is loose. If clothes get wet (wet t-shirts, anyone?) they lose much of their protective effect.

 

 

Dear Dr. Eva,

I’ve heard about the Keto Diet and have friends who have lost a lot of weight with it. My doctor says she does not recommend my trying this, but I’m tempted. Is it for real?

Gettin Ready for the Beach

 

Dear Gettin Ready,

About those friends of yours who have had great success – how long have they kept the weight off?

The very low carbohydrate diet is also called the ketogenic (keto) diet; it is very similar to the Atkins diet. Popular on and off since the 1960s, these diets have been having another revival in the last few years. The keto diet turns the food pyramid upside down by recommending eating mainly protein and fat with little or no simple or complex carbohydrates (starches and sweets). Fats are the most calorie intensive of all forms of food, so it’s a little hard to understand why this works. Ketogenic diets cause weight loss with high calorie intake by changing normal metabolism to ketosis. Normal metabolism is based on glucose (sugar): carbohydrates, proteins, and fats are all broken down to glucose, which is used as fuel for the body. If a person eats a diet that contains no carbohydrates, the body is not able to break foods down into glucose and instead begins to consume stored fat for energy. Since fat breakdown is a less efficient way to generate energy, not all the calories in food are used for energy and weight loss is faster.

The high protein content of the keto diet stresses the kidneys, which makes this diet risky for people with high blood pressure or diabetes. The high fat content raises cholesterol levels, which increases the risk of heart disease and kidney stones. But the biggest practical problem with the keto diet is that as soon as a person starts to eat any carbs at all, the body switches out of ketosis and all the weight that’s been lost is rapidly gained back in weeks or months, usually plus 10% extra. Even in the “maintenance” phase of the keto diet, carbs are restricted to 100 grams a day. To give you an idea what this means, 100 grams of carbs could be one serving of vegetables and two pieces of fruit plus either one slice of bread or 1/3 cup cooked rice or pasta. I have never yet met a person who could maintain this very restrictive diet for over two years, and most people can’t manage it for more than a few months.

So the bottom line is: the keto diet may help you take pounds off quickly and look thinner at the beach this summer, but it’s not likely to keep the pounds off through next summer. The only reliable choice for long term weight loss is permanent change in eating patterns, meaning permanent changes to lower overall calorie intake. Exercise is helpful to any person’s overall health, but it has relatively little benefit for weight loss, especially in women. Consider the fact that twenty minutes on the treadmill at a brisk walking pace uses less than 50 calories of energy. That means it would take two hours on the treadmill to burn off the calories from one chocolate bar or 1.5 ounces (half a small serving) of French fries.

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Dr. Eva Hersh, MD
Dr. Eva Hersh, MD
Eva Hersh is a family physician. Send your comments and questions to her by email at dreva@baltimoreoutloud.com