Dear Doctor: I've been hearing that eating six small meals per day instead of three large ones is better for your health and even helps with weight loss. When I try it, though, I wind up feeling hungry all day. Are six meals really better than three?

Dear Reader: Your question arises from recent news reports, but it has been debated for centuries in one form or another. From the ancient Romans, who believed that a single meal per day was the path to good health, to a Canadian study in the 1980s that touted the benefits of a "nibbling diet" of 17 snacks per day, the question of meal frequency has long been a topic of great fascination.

The premise behind eating smaller and more frequent meals is the control of blood sugar, also called blood glucose. This refers to the glucose, a type of sugar that is extracted from the food we eat. When digestion is complete, glucose is carried by the bloodstream and throughout the body to supply our cells and organs with energy.

When blood glucose levels drop, hunger and cravings spike. By eating six small meals per day, the thinking goes, you're ensuring that blood glucose is available at all times. By controlling the trigger for cravings, you'll eat less and won't be as likely to give in to the siren song of that bag of chips or chocolate bar.

But does it work?

While the logic is solid, results have been mixed. Participants in a study who ate six small meals showed no metabolic advantage over those who ate three large meals. What did separate them from the three-meal group was that they reported higher levels of hunger and an increased desire to eat.

Another study found that eating smaller meals more frequently throughout the day had little effect on fasting glucose levels. However, it did conclude that waiting until the end of the day to eat the majority of calories had a detrimental effect on blood glucose control.

In fact, intriguing data from recent studies supports the idea that intermittent fasting is beneficial. The shift in the way the body metabolizes food after a weekly fast as brief as 16 hours was found to have measurable health benefits.

As research continues and we add to the body of knowledge regarding meal frequency, we can fall back on what we know for sure -- that what you eat can play a significant role in maintaining good health. It's the total calories consumed and the nutritional quality of those calories that matter.

However many meals per day you decide to eat, be sure to limit your calories to a healthy level. Processed foods, refined sugars and sugary soft drinks are empty and even dangerous calories, so steer clear. Lean proteins, vegetables (specifically, leafy greens) and fresh fruit are the building blocks of a healthful diet. And we know you've heard it before, but we'll say it again: For the best chance at ongoing good health, remember to exercise.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095.)

Dear Doctor: Given a choice, I'll always choose white wine over red. But a recent study linking white wine to increased melanoma risk made me reconsider. Am I overreacting?

Dear Reader: This is a difficult question without a simple answer -- so let's start with some basics. Alcohol metabolizes into the chemical acetaldehyde, which can cause DNA mutations that lead to cancer. To date, alcohol has been associated with an increased risk of cancers of the breast, colon, liver and pancreas.

A 2014 analysis of many different studies published in the British Journal of Dermatology found an 18 percent increase in melanoma among people who drank more than one alcoholic beverage per day, regardless of the type. This analysis was based on retrospective studies, which are studies assessing people's past habits after a diagnosis has been made.

Prospective studies follow patients prior to the diagnosis of disease. The research to which you're referring was that type of study, and was published in the journal Cancer Epidemiology, Biomarkers and Prevention. For their analysis, researchers looked at data on disease outcomes from three studies of health care professionals and tied those outcomes to potential risk factors. The three studies combined followed a total of more than 210,000 people over a period of more than 18 years. In the studies, participants were asked to state their level of alcohol consumption and to also state what type of alcohol they consumed.

Researchers found that overall, 1,374 people (less than 1 percent) were ultimately diagnosed with melanoma. Those who drank alcohol, however, had a 14 percent increase in the rate of melanoma, and that number increased to 21 percent in those who had one or more drink per day. Note that people who drank more alcohol also reported higher rates of smoking, caffeine intake and previous severe sunburns. The authors adjusted for this, so the data still appears relevant.

So yes, alcohol appears to slightly increase the risk of melanoma.

As for wine, some types -- especially white wines -- have more acetaldehyde and thus could have a greater ability to increase cancer risk than other types of alcohol. But when the authors looked at the type of alcohol consumed, the results between the three studies varied tremendously.

Consider that in one study, of male health care professionals, the researchers found a greater rate of melanoma among men who drank white wine one to three times per month compared to those who drank white wine two to four times per week. Even taking that finding into account, the authors overall found a 13 percent increased rate of melanoma with each drink of white wine per day. They did not find such a high rate with other types of drinks.

The current study has two potential problems, however. One is that the authors did not differentiate whether drinkers of white wine also drank other types of alcohol. Also, and this may be the biggest issue, because white wine is often drunk cold, people who drink white wine may be more likely to live in sunnier places and thus have more sun exposure.

The authors did look at this second point and found that the majority of melanomas that appear to be related to alcohol consumption occurred on the less-sun exposed areas of the chest, abdomen and back. If the melanomas were linked to sun exposure, instead of wine consumption, the cancers would have been more likely on exposed areas of skin, such as the arms and face.

In summary, drinking alcohol does appear to slightly increase the risk of melanoma. While this study on the impact of white wine does not appear convincing, white wine drinkers should consider the fact that acetaldehyde is carcinogenic and white wine has more acetaldehyde.

Myself, I will reflect on this the next time I have a glass of pinot grigio on a hot summer day.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095.)

Dear Doctor: It's been two weeks since our son was born, and my wife seems to be having a hard time. She cries easily and has a lot of anxiety. Is this just baby blues, like my mother says, or is it postpartum depression?

Dear Reader: Congratulations on welcoming a new baby! Your lives have undergone an enormous change, and that's at the heart of your wife's difficulties. Both in the short-term disruption of the so-called "baby blues" and the more serious struggle of postpartum depression, the physical, emotional and hormonal changes a woman goes through after she gives birth can often pose challenges.

First, let us reassure you that at two weeks postpartum, it's perfectly natural for a new mother to feel overwhelmed. Up to 80 percent of new mothers report symptoms of mood swings, anxiety, mild depression, weepiness and negative thoughts or feelings in the first few weeks after the baby arrives.

Your wife's body is not only recovering from the physical and emotional rigors of the birth process, but it is also now returning to its pre-pregnancy state. That means she is experiencing a sudden drop in hormone levels -- estrogen and progesterone in particular -- which have been at record levels during her pregnancy. Add in sleep deprivation and the seismic changes to her daily routine as she learns new tasks and takes responsibility for a new life, and it's little surprise that she feels overwhelmed.

When these symptoms don't go away after several weeks, or if they become more severe, then postpartum depression becomes a possibility. When this is the case, seeing a primary care physician is vital.

Symptoms of postpartum depression mirror those of major depression. These include a sad or empty feeling that won't go away, feelings of hopelessness or worthlessness, pervasive pessimism, a change in sleeping or eating habits, withdrawal from loved ones, and often a lack of connection to or interest in the new baby. Between 11 and 18 percent of new mothers experience postpartum depression. Fortunately, most women who seek treatment for postpartum depression will recover.

Meanwhile, there's a lot that you can do to help your wife right now. Simply listening is important. Get her to talk about how she's feeling and what she's going through so she knows that you care and understand. It's quite likely you both have some of the same feelings, and sharing them can help build up your bond.

Help around the house without being asked. Make a meal, do housework, arrange for her to have some time to herself. Something as simple as getting outside can make a big difference. A daily walk will be good for both of you. Even a drive through the neighborhood just to look around can bring welcome distraction.

The baby blues are an isolating experience that comes at a time of life when women are told they should be happiest. By stepping up to lend a hand, you're not only helping your wife recover, you're also setting the foundation to a parenting partnership.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095.)