Healthy Eating

What makes processed foods so bad for you?

DEAR DOCTOR K: Most nutrition advice starts with "avoid processed foods." What exactly are processed foods? Are they all bad for you?

DEAR READER: A processed food is any food that has been changed in some way from its original state. Processing includes canning, cooking, freezing, dehydration or milling. As you say, nutrition gurus often urge us to spurn processed foods. I spoke with Stacey Nelson, a registered dietitian and manager of clinical nutrition at Harvard-affiliated Massachusetts General Hospital. She noted that most food needs to go through some degree of processing in order to make it edible and digestible.

What diet can help with IBS?

DEAR DOCTOR K: I have irritable bowel syndrome (IBS), and I hear there is a diet to help that. Can you tell me about it?

DEAR READER: Unfortunately, IBS is pretty common. Symptoms include cramping, diarrhea, gas and bloating. But you are right: Research has identified certain foods that tend to trigger IBS, and avoiding these foods can help you reduce your symptoms.

What’s the difference between soluble fiber and insoluble fiber?

DEAR DOCTOR K: Everyone agrees that you benefit from fiber in your diet. But it seems some people prefer soluble fiber and some insoluble fiber. What's the difference, and which is best?

DEAR READER: Dietary fiber consists of the indigestible parts of plant foods. We need about 20 to 35 grams of fiber a day. As you note, there are two kinds of fiber. Soluble fiber dissolves in water; insoluble does not. Both are important for healthy digestion, and both can help prevent heart disease, obesity, diabetes, diverticulitis (an intestinal malady) and constipation.

Will my son grow out of his childhood obesity? I don’t want to make a big deal about his eating habits.

DEAR DOCTOR K: My 9-year-old son is very overweight. I don't want to make a big deal about his eating habits, because I assume he'll grow out of his obesity later in life, and because we already set so many rules for him to follow. Do you agree?

DEAR READER: I wish I could, but I can't. A child's eating habits, and weight, can adversely affect his or her health later in life. The healthy eating habits you set with young kids not only influence their eating habits later in life, they also influence the chemistry of your kids' bodies so they are less likely to get fat as adults. All the talk about childhood obesity is not just media hype.

Do adults need milk?

DEAR DOCTOR K: My parents made us drink milk every day, and I've continued that as an adult. A friend just told me that adults don't need milk, and that it can even be bad for you. What's the truth?

DEAR READER: Like you, we always had milk when I was a kid. In fact, the coming of the milkman to deliver the milk at home (remember him?) was an important event each day. These days, I have milk on cereal, but I don't drink it by the glass. As with most things, there are both benefits and risks.

What is the Mediterranean diet and is it actually healthy for you?

DEAR DOCTOR K: In some of your columns you've said that the "Mediterranean diet" is healthy. First, what is a Mediterranean diet? Second, what proof is there that it really is healthy? Call me "Skeptical."

DEAR READER: Well, "Skeptical," prepare yourself for a fairly emphatic reply. Because when I think skepticism about something important is misguided, I tend to unload. The Mediterranean diet is the traditional diet of people in countries near the Mediterranean Sea. The diet is rich in plant foods. These include fruits, vegetables, grains, beans, nuts and seeds. Animal protein is consumed chiefly in the forms of fish and poultry. Olive oil is the principal fat. And wine is taken with meals.

What are good fats and bad fats?

DEAR DOCTOR K: I've read in your column about "good fats" and "bad fats." I've also heard that recent studies challenge which fats are "bad." Can you shed a little light on this issue?

DEAR READER: I don't blame you for being confused. One problem with medical studies is that they don't always agree. That's why we often need a lot of them to determine the "truth." Let's start at the beginning. For years, you probably heard that all fats were bad for you and carbohydrates ("carbs") were good. That was nonsense. We need both fats and carbs in our diet.

I’m 80 and I eat a lot less now, am I getting enough nutrients?

DEAR DOCTOR K: I'm in my 80s. These days, I'm not very hungry and I eat a lot less than I used to. My daughter is worried I'm not getting enough nutrients. Is she right?

DEAR READER: Of course, I don't know if you are getting enough nutrients, but your daughter is right to be worried about it. For one thing, you say you're not eating much. People normally start to have a reduced appetite as they get into their 70s and 80s, but it's not a dramatic change.

Is a vegetarian diet really better for your health?

DEAR DOCTOR K: I'm thinking of becoming a vegetarian. But I need to be certain -- is a vegetarian diet really better for your health?

DEAR READER: The answer is: it depends. Just avoiding meats and eating only vegetables can be accomplished in both healthy and unhealthy ways. After all, a vegetarian who subsists on meat-free pizza and grilled cheese sandwiches isn't doing himself any favors. And, believe it or not, I've had more than one "vegetarian" patient whose diet was like that. However, for a while now, it's been clear that healthy, plant-based diets may improve long-term health. Such healthy vegetarian diets include proteins from vegetables (peas, spinach, broccoli, Brussels sprouts and many others) and carbs from whole grains.

What are considered bad carbs?

DEAR DOCTOR K: You talk about "good carbs" and "bad carbs" in your column. Since I know new studies sometimes change thinking, I'm wondering if "bad carbs" are still bad -- because I like eating them.

DEAR READER: I've got some bad news for you. If anything, the case against bad carbs is growing stronger. To refresh everyone's memory, let's distinguish good carbs from bad carbs. Carbohydrates are found in a broad range of foods; some are healthy and some aren't. Table sugar, fruits and vegetables, and grains such as rice and wheat are all carbs. But they aren't equal in how they affect your body.