Eating well can help kids with cancer feel better and cope with the side effects of cancer or its treatments.

To keep up their strength and deal with side effects, kids should stay hydrated, take only doctor-recommended supplements, and eat as well as possible, even though that sometimes can be hard. For some kids undergoing treatment, that might mean getting enough to eat; for others, it could mean making sure not to eat too much.

Staying Hydrated

Kids being treated for cancer often lose a lot of water from vomiting, diarrhea, or by just not drinking enough. This can lead to dehydration. To avoid it, make sure your child gets plenty of liquids. Tap, filtered, or bottled water is best, but your child can also get fluids from other sources, like juices (100% fruit juice is best), fruits and vegetables that contain lots of water (like watermelon and cucumbers), and soups.

Water helps with nearly every body function — from digestion and metabolizing fat, to flushing toxins from the body and maintaining body temperature. Getting enough fluids also helps prevent constipation, a condition that can make a child even less inclined to eat.

Eating Right

Every kid with cancer has specific nutritional needs, so it's important to talk to a dietitian about what would be best for your child. In general, kids with cancer have an increased need for protein, carbohydrates, vitamins and minerals, and healthy fats.

Protein helps the body grow, repair tissues, build blood cells, and replenish the immune system. Getting enough protein can help your child heal faster from the side effects of radiation and chemotherapy, while also helping to prevent infections. Foods like cheese, eggs, milk, yogurt, lean meats, poultry, fish, beans, peanut butter, nuts, lentils, and soy are all good sources of protein.

Carbohydrates are the body's fuel, providing energy for cells and helping to maintain organ function. Good sources of carbs include breads, pasta, potatoes, rice, cereals, fruits, corn, and beans. Whole-grain breads and pastas are usually best because they add fiber, which helps kids feel fuller longer and prevents constipation, a common side effect of cancer treatment.

Fats help the body store energy, insulate body tissues, and carry certain vitamins throughout the bloodstream. Fats also are dense in calories, which is important to a child who might be losing weight during treatment. Not all fats are created equal, though. Unsaturated fats that are found in fish, nuts, olive oil, and vegetables like avocados are much healthier than saturated fats and trans fats that are found in red meats and greasy, fried foods.

Dietary supplements usually aren't recommended, as they can interfere with some cancer treatments. Don't give your child any supplement unless your health care provider recommends it. It's best for kids to get their nutrients through food.

Helping Your Child Eat More

When kids aren't feeling their best, it can be hard to get them to eat. Try these tips to help your child:

• Offer smaller, more frequent meals. Also serve meals on a smaller plate, as a large plate of food can seem like too much to someone with a decreased appetite.
• Always have food on hand. Whether it's a breakfast bar, a liquid nutrition drink or shake, crackers, or fruit, keep snacks handy in case your child suddenly gets hungry.
• Try blander foods. If your child seems sensitive to strong smells or tastes, stick to plain meals like breads, pastas, rice, and broth-type soups.
• Experiment with food temperatures. Many kids undergoing treatment prefer foods that are served at room temperature rather than very hot or too cold.
• Avoid acidic foods. If mouth sores are a problem, stay away from acidic foods like orange juice, lemonade, and tomatoes.
• Make foods easier to swallow. If swallowing is difficult, try puréed foods, soups, shakes, or smoothies. A straw may help them go down easier.
• Don't offer liquids with meals. Serve drinks in between meals, instead of with meals. This way, your child won't fill up on fluids and will have an appetite to eat. (But if your child has mouth sores or dry mouth, offering drinks with meals actually helps the food go down.)
• Make up for lost calories. Your child might not want to eat very much when getting chemotherapy. Between treatments, make up for that with things like high-calorie bars and milkshakes. Ask your child's doctor for recommendations.

Helping Your Child Eat Less (or Better!)

Many kids undergoing cancer treatment tend to eat less and lose weight because their appetites are affected.

But some kids actually have increased appetites, especially if they're on steroid medicines that can make them hungrier. This can lead to fluid retention and weight gain. These problems usually go away after treatment ends. But in the meantime, it's important for kids to maintain a healthy weight.

These tips can help:

• Set a mealtime schedule. Serve three moderate-sized meals a day, plus 1–2 snacks, and make sure your child sticks to that schedule. Encourage your child to wait for at least 20 minutes after eating something before asking for more. (In general, it takes kids this long to realize they're full.)
• Limit salt intake. Help prevent fluid buildup by limiting the salt in your child's diet. Avoid fast foods, processed foods, frozen meals, and snacks like chips and pretzels. Use spices other than salt to season foods made at home.
• Serve fruits and veggies first. Offer fruits and vegetables at the beginning of the meal. If served first, they taste even better to a hungry child. Follow these with whole-grain products (like breads and pastas). They're high in fiber and keep kids feeling fuller longer.
• Provide healthy snacks. Keep only healthy foods in the house for snacking, and bring healthy snacks with you when you go out. Limit your child's intake of soda and sweets, which are both loaded with empty calories.
• Stay active. Help keep your child's mind off eating. Try activities such as sports, games, reading, or hobbies. To help burn excess calories, your child should try to stay active and get plenty of exercise if they feel up to it.
• Keep food out of sign and out of mind. Limit food-related TV shows and keep food in a cabinet, not on the counter.
• Limit liquids with calories. Juices, sodas, and sports drinks have extra calories and very little nutrition. And they don't satisfy hunger.

When the steroid or other treatment ends, your child's appetite should return to normal and may even decrease for a short time. This is normal and not typically a cause for alarm. Your child's doctor probably will expect the weight loss associated with this and will keep a close eye on it.

Eating to Reduce Side Effects

Cancer and its treatments can cause a number of side effects, including nausea, vomiting, dry mouth, mouth sores, constipation, and diarrhea. They also can:

• heighten sensitivity to food smells or temperatures
• make it hard to swallow
• cause changes in taste that might make kids not like foods they once enjoyed

Fortunately, after treatment ends, these problems go away.

In the meantime, help with nausea and vomiting by making sure your child takes all medicines correctly and eats the right things. Offer bland foods, especially on days when your child has treatment. Avoid salty, sweet, fatty, and fried foods. Food smells also can play a part in nausea. Consider offering foods with little or no smell, and don't cook hot foods around your child.

To help control diarrhea, give your child foods like white bread, bananas, white rice, and applesauce that are easy to digest. Avoid dairy products; greasy, spicy, or fried foods; food and drinks with caffeine (like coffee, tea, and chocolate); high-fiber foods; raw fruits and vegetables; and foods like cabbage and broccoli that can cause gas. Kids with diarrhea should drink more than usual to replace lost fluids.

To help control constipation, offer your child high-fiber foods, such as fruits, vegetables, nuts, and whole-grain breads and cereals. In addition to water, give your child fruit and vegetable juices (such as prune juice), and warm liquids like tea.

A change in food preferences might seem like an insignificant problem, but if it causes your child to lose interest in eating, it won't be. You'll need to manage this for as long as it lasts, which can be weeks or even years:

• Help your child to practice good oral hygiene by brushing teeth regularly and rinsing out the mouth often — this can help decrease mouth sores and make food taste better.
• If your child is sensitive to the taste of metal, try using plastic forks and spoons instead.
• Encourage your child to try new foods. Those with strong flavors can often mask the taste changes in your child's mouth.
• Keep a wide variety of foods handy to help meet your child's changing tastes.

Safe Food Handling and Prep

Kids with cancer are at high risk for infection, so it's very important to know how to handle and prepare food safely. This means washing your hands well before handling food or after touching things like raw meat and poultry.

It also means things like keeping hot foods hot and cold foods cold. Prepared food should never sit at room temperature for more than an hour, and leftovers should be eaten within a few days.

Raw fruits and veggies should always be washed well before they're eaten. This includes melons or any other thick-skinned fruit you might cut with a knife. Cooked foods should be cooked well before they're served.

Encouraging Good Eating Habits

When kids have trouble eating enough, it can be easy to give in and let them eat anything, healthy or not, just so they're getting some calories. But it's important to encourage healthy eating habits.

Eating nutritious foods will help make your child less likely to binge on sweets or fried foods. And remember, someday the treatment will end, and your child's appetite will go back to normal. When it does, the good eating habits built now will help your child choose healthy options.

It can be tricky to keep your child focused on nutrition during treatment, but it's important to try. Kids who eat well and stay hydrated are better able to tolerate and stay on schedule for treatments, steer clear of infections, keep a healthy weight, and stay strong enough to enjoy favorite activities — all of which increase their chances for the best possible outcome.