Dear Doctors: I was very interested to read your column that talked about the fat around your organs, and how when you have too much, it is bad for your health. I have also heard of something called brown fat, and that it’s actually a good thing. Can you please explain?

Dear Reader: When we think of fat, it is often subcutaneous fat that comes to mind. That’s the layer of fat that lies just beneath the skin that you can see (it jiggles) and pinch. Visceral fat, by contrast, is found deep within the abdomen. It helps cushion and protect the internal organs, including the stomach, intestines, liver, pancreas and kidneys.

A certain amount of visceral fat is important to health and well-being. But this type of fat is hormonally active. Having too much can be a danger to health. As we explained in the column you read, excessive visceral fat is linked to an increased risk of diabetes, coronary artery disease, heart disease, high blood pressure and systemic inflammation.

Another important kind of fat produced by the body is brown fat. Also known as brown adipose tissue, it plays an important role in regulating body temperature. As the name suggests, brown fat is darker in color than the rest of the fat in the body. This is due to a high concentration of cellular organs, known as mitochondria, which produce energy. It means unlike white fat, which only stores calories, brown fat can burn them, too.

That’s where temperature regulation comes into play. When the body gets cold, brown fat is activated. It begins to generate the heat the body needs by burning calories. Recent research also suggests that brown fat plays a role in blood sugar metabolism.

Brown fat has an interesting history. Although it was visually identified as early as the 16th century, it wasn’t until 1961 that scientists confirmed it generates heat. It was also initially believed that brown fat is only present in babies. Newborns have a significant amount of brown fat -- up to 5% of their body weight -- which helps to keep them warm. It is found primarily in the upper back, neck and shoulders. Those fat cells dissipate as children grow into adolescence. They were believed to vanish completely in adults. In 2003, thanks to advancements in imaging, it was discovered that brown fat persists in adults, but in much smaller amounts.

In adults, brown fat constitutes less than 0.5% of body weight. People who are lean have more of it than those with a higher body-fat percentage. And unlike the centralized deposits seen in newborns, scans of adults find small amounts of brown fat in the tissues of the neck, kidneys, adrenal glands, chest cavity and along the spine.

Due to its thermogenic nature -- that means it burns energy -- brown fat has become a focus of research into obesity and weight loss. You can protect the brown fat in your own body by eating a healthful diet, getting regular exercise and spending periods of time in cooler temperatures.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Hello, dear readers, and welcome to a bonus letters column. We recently focused on strategies for healthful eating and drinking during the holidays. Several of you had previously shared your own creative approaches, and we’re happy to pass them along.

-- One challenge that many of us face with holiday eating is the abundance of treats in the house. We heard from a reader whose home is a baking hub for her extended family.

“My three kids, and all their kids, love to come to Grandma’s house to do Christmas baking. I love the tradition, but it means we always have cookies or cupcakes or slices of cake or pie left behind as a thank you,” she wrote. “I’ve got a serious sweet tooth and not a lot of willpower. I made it a rule that before I can have even a nibble, I have to have a serving of salad. To make that easier, I make a big batch every morning. I find that by the time my serving of salad is gone, so is my craving for the cookie.”

What an interesting idea! When you start with that salad, you’re not only sating your hunger, you’re also resetting your palate. (And improving blood sugar control.) That makes it easier to resist bingeing on sweets. This approach is also easily customizable with other vegetables, fresh fruits and leafy greens.

-- Between family, friends and the office, holiday get-togethers can be a landmine of temptation. One reader explained his approach to a moderate -- but also fulfilling -- party season.

“I’ve got a few favorites that show up during this time of year, like pecan pie, champagne, hot chocolate and cookies with nuts in them, and at parties I focus on one of those,” he wrote. “When I get there, I’ll do a quick cruise of the food and drink tables to see what’s what. Then I’ll choose a favorite that we don’t usually have at home, or that comes around only during this season. By the time New Year’s rolls around, I’ve satisfied all of my cravings.”

Selective splurging is a terrific idea. And before a party, having a high-protein snack that satisfies hunger makes it easier to stick to portion goals.

-- Most Americans don’t eat enough fiber, something that doesn’t change during the holidays. We heard from a reader who turns the tables on that with her hostess gift and creates a safe haven for her own holiday party eating.

“Instead of wine or flowers, I bring our hosts a pretty serving platter. I stock it with vegetables, nuts, roasted cauliflower and a delicious dip,” she wrote. “I wrap the whole thing in cellophane, add a bow and voila, it’s a lovely gift. The platter makes it to the holiday table and is usually picked clean.”

Thank you for sharing another great idea. People attending a potluck can also consider a veggie- or fiber-forward contribution.

We hope everyone has an enjoyable time as the holiday season races by. (Seriously, how does it go so fast??) We will be back with our regular letters column in a few weeks.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctors: I just turned 36, and I’m feeling the effects of drinking more than I used to. My boyfriend and I both have big families, so during this time of year, we have wall-to-wall holiday parties. Last year we did dry January, but this year we want to try a dry-ish December. How do you do that but still have some fun?

Dear Reader: We’re sorry to get to your letter so late in the holiday season, especially because it echoes the concerns that fill our inboxes as the leaves begin to fall. People are looking for a way to thread the needle between the rigor of complete abstinence and the ill effects of overdoing. We recently addressed the issue of holiday overeating, a challenge many of us face. Your question gives us the opportunity to talk about alcohol, which, like rich foods, becomes abundant during this time of year.

Surveys show that drinking during the holiday season spikes -- often significantly. Many respondents report that having just one drink at each holiday gathering adds up to double their normal intake. There’s only a handful of weeks between Thanksgiving and New Year’s Day, but the additional alcohol use can take a toll. Adverse health effects include impaired blood sugar control, an increase in blood pressure, added empty calories, changes to mood and mental health, poor sleep and lowered resistance to risky behaviors.

Health data show that emergency room visits in which alcohol has played a role dramatically increase during this time of year. So does the risk of being involved in an alcohol-related car accident. Data compiled by the National Highway Traffic Safety Administration finds that car crashes due to impaired driving are 40% higher during the holidays. The bottom line is that your decision to limit drinking during that time is a wise one.

You said you and your boyfriend were considering a “dry-ish” December. A good way to begin is by clearly defining the “ish” part of that goal. Look at your calendars, and decide ahead of time at which events you will indulge in alcohol and which you won’t. When you do drink, set a limit and stick to it. That means not only counting the number of drinks, but also being aware of their size. If you’ve allowed for a refill, space it out with one or more nonalcoholic beverages.

Food slows alcohol absorption. That makes it important to always eat something before you drink and also as you drink. Fiber and protein help stabilize blood sugar, so start with meat and veggies before you hit the desserts.

When declining a drink, social pressure can be an issue. Coming prepared with a humorous or gracious refusal can deflect the attentions of a persistent host. Having your nonalcoholic beverage served in a wine glass or a champagne flute will also help you fly under the radar.

Another useful guideline is to set a specific time at which you will stop drinking. This is particularly important if you don’t have a designated driver. With a bit of planning -- and let’s face it, a bit of willpower -- you can meet your dry-ish December goals while still enjoying the pleasures of the festive season -- and if not this one, perhaps next year.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)