Healthy Eating

What’s the difference between a good and bad carbs?

DEAR DOCTOR K: In your column you often distinguish between "good" and "bad" carbohydrates. What makes a carb good or bad?

DEAR READER: Carbohydrates -- carbs -- occur naturally in a variety of foods, from fruits, vegetables and milk, to breads, cereals and legumes. Carbs are also added to many foods, often in the form of sugar. Your digestive system transforms carbs into glucose (blood sugar). They are your body's main source of energy. Whether a carb is "good" or "bad" depends on several factors. Some of the most important are:

How does sugar increase the risk of heart disease?

DEAR DOCTOR K: I've read that sugar increases the risk of heart disease. How does it do that? Also, any advice for those of us with a sweet tooth?

DEAR READER: So far as we know, sugar doesn't directly harm the heart. But it sure indirectly harms the heart, by promoting the following cardiac risk factors -- problems that lead to heart disease: OBESITY: Excess calories contribute to obesity. Added sugar is a major source of excess (and empty) calories. Overweight and obese people are at greater risk for heart problems. Today, we're discovering that the cells containing fat make hormones that travel in the blood and have many harmful effects on the heart.

Is it possible to go off blood pressure medication through diet and exercise?

DEAR DOCTOR K: Is it possible to get off blood pressure-lowering medication through diet and exercise?

DEAR READER: Yes, it is. I've seen many patients commit to lifestyle changes and get off blood-pressure medicines entirely. More often, I've seen that a commitment to a healthier lifestyle allows people to greatly reduce how much medication they take, even though they still need some medicines to control their blood pressure. While many people, myself included, would like to not have to take medicines at all, being able to reduce the dose is a big deal. Many of the side effects of medicines are reduced or eliminated by reducing the dose.

What fish should I avoid while pregnant?

DEAR DOCTOR K: I recently found out that I'm pregnant. I'd like to continue eating fish, but I understand some fish contain mercury, which could be harmful to my baby. What fish should I avoid?

DEAR READER: Fish are a great source of lean protein, and many types are rich in heart-healthy omega-3 fatty acids, which help brain and nerve development and protect the heart. In fact, current dietary guidelines recommend that women who are pregnant eat 12 ounces of seafood a week. But as you noted, some species of fish do contain worrisome amounts of methylmercury. This toxin is especially dangerous to developing brains. High-mercury fish you should avoid during pregnancy include swordfish, shark, king mackerel and tilefish.

Am I getting enough iodine in my diet?

DEAR DOCTOR K: I cook with kosher salt, which doesn't contain iodine. Am I getting enough iodine in my diet? Can I get iodine from other foods?

DEAR READER: Before I answer your question, I'll need to explain a little about the thyroid gland and how it works. The thyroid is a small, butterfly-shaped gland that perches with its wings wrapped around the front of your windpipe, below your voice box. This gland influences the rate at which every cell, tissue and organ in your body functions. It does this primarily by secreting thyroid hormones.

How can I make restaurant meals healthier?

DEAR DOCTOR K: I travel regularly for work, so I have to eat out a lot. Could you give me some strategies to make restaurant meals healthier?

DEAR READER: Eating out can ruin even the healthiest diets. That's because restaurants -- and not just fast-food joints -- tend to overdo the butter, sugar and salt. I spoke to registered dietitian Kathy McManus, director of the Department of Nutrition for Harvard-affiliated Brigham and Women's Hospital. She assured me that you can enjoy a meal (or several) on the road if you follow a few handy tips:

Should I switch to diet soda to help cut down on sugar?

DEAR DOCTOR K: You often advise cutting out sugary soda drinks. Should I switch to diet soda?

DEAR READER: Sugary soda drinks have no place in a healthy diet. Excess sugar leads to weight gain -- and obesity increases the risk of many serious health conditions, including heart disease and Type 2 diabetes. As I always say when giving dietary advice, I'm talking about a regular practice, not an occasional sin. If you like a non-diet (sugary) drink once in a while, enjoy it.

Should I try a low-fat, low-carb, or Mediterranean diet?

DEAR DOCTOR K: I want to go on a diet and am trying to decide between low-fat, low-carb and Mediterranean. What do you think?

DEAR READER: Your first two options -- low-fat and low-carb -- are too simple. There are "good" fats and "bad" fats, and "good" carbs and "bad" carbs. You don't want a diet that is low in good fats or good carbs. You want a diet that is low in bad fats and bad carbs.

How can I find the time to prepare and eat healthy meals?

DEAR DOCTOR K: Between my job and kids, I rarely have time to prepare and sit down to a healthy meal. I've had my fill of fast food and energy bars. Any suggestions?

DEAR READER: It certainly is easy to eat badly. For one thing, as you say, many of us have very hectic schedules. Fast food is appealing because it's fast. But fast food is often unhealthy. You don't have to sacrifice nutrition when you're on the go.

What is a list superfoods that support heart health?

DEAR DOCTOR K: You've written about "superfoods" that deliver a lot of nutritional bang for their buck. Do you have a list of superfoods for heart health?

DEAR READER: Many foods -- from the everyday to the exotic -- are rich in nutrients that help keep heart disease at bay. That's good news, and it's been documented in many scientific studies. My colleagues in nutrition science at the Harvard School of Public Health and Harvard Medical School have published the following list of heart-healthy superfoods. They and I use the word "superfoods" advisedly. Obviously, no food offers anything like perfect protection against any illness.