Nutrition for strength, when ...

We've all heard the old adage "you are what you eat" -- and it's never as true as when you are feeling under the weather. During these times, what you eat and when you eat it can preserve strength, boost immunity, and help you feel better -- quicker.

But for people battling arthritis, cancer, depression, and other conditions that can affect appetite, eating right is much easier said than done. To help, WebMD compiled this list of nutrients you need, complete with suggestions for how to get them quickly and easily.

Harnessing the Power of Protein

Hands down, "the most important nutrient when you are feeling weak is protein," says Rachel Beller, MS, RD, director of the Brander Nutritional Oncology Counseling and Research Program at the John Wayne Cancer Institute in Santa Monica, Calif. "We need protein for strength and for maintaining proper body mass."

If you have cancer, are not hungry, and don't eat, "you could become weakened to the point that treatment can be halted," she says. To avoid this scenario, "psychologically think of food as medicine."

When you feel too ill to eat, consider a high-calorie drink, Beller suggests. "Take some easily-digestible protein powder (such as whey) and put it in a blender with some almond milk (which is also easy to digest) and some frozen berries, so it has a cool temperature, but it's not icy," she says.

"Sliced bananas or yogurt can be added to make it creamy," she says. "Blend and drink." It's high-protein (containing roughly 21 grams of protein, which is the equivalent to 3 ounces of chicken), contains one to two servings of fruit, and is rich in calcium, Beller says.

Another good choice: "Healthy, high-protein foods such as nuts are usually well tolerated when you are nauseous," she says. Almond butter, cashew butter on crackers, or pre-prepared soup with beans also pack a good protein punch.

Sally Pataky, MS, RD, recommends eggs, as well as shakes, to her clients at the City of Hope Cancer Center in Duarte, Calif. "It takes a lot of energy to chew things," she says. "I suggest eggs because they are the best quality protein and they are easy to eat."

Concentrating on Calcium

Calcium is an essential mineral that all women need from adolescence on, says clinical nutrition specialist Frederic Vagnini, MD, FACS, medical director of Pulse Anti-Aging Center in Scarsdale, N.Y. "It's an absolute must and a no-brainier."

For optimal bone health -- especially among people taking medications such as corticosteroids that deplete bone density -- aim for 1,200 to 1,500 mg of calcium a day from both food and supplements.

"Yogurt is rich in calcium and easy to get down," he says.

Taking a Daily Multivitamin

Most nutritionists, including Beller, suggest that people try to get their vitamins from whole foods. Food contains many vitamins and minerals, and their synergistic effect is probably more beneficial than vitamin supplements. Still, no one has a perfect diet. So Beller and Vagnini suggest one multivitamin each day.

"I recommend everyone take a multivitamin, especially those who are elderly or who have a chronic illness," says Vagnini. He says "poor appetite is not an uncommon problem in the elderly and it is also worsened by poor teeth, fatigue, and a decrease in mental acuity."

Finding Time for Fiber

Most people need 20-35 grams of fiber a day, depending on your gender and age, according to the American Dietetic Association. In addition to improving regularity, adequate fiber can help prevent several forms of cancer and heart disease.

"Generally speaking, fiber comes from fruits, vegetables, and whole grains," Vagnini says. But if your appetite is compromised, "one of the things that you may try is a fiber supplement or try oat bran cereal mixed with some milk and fruit."

Fresh fruit is another great source of fiber. Also, some meal-replacement drinks and bars have fiber in them.

Certain pain medications and cancer medications can be constipating, so fiber can help keep you regular. But she cautions against filling up on bran because it is important to get calories from other foods as well.

Fitting in Fat

"We encourage people to eat fats like avocado and even ice cream," Pataky says. "We are not as concerned about fat types as we are about getting in calories because if you lose weight when you are sick, it's not just fat loss, it's muscle loss as well and that is very hard to get back," she says. "It's important to get enough calories and fat is high in calories," she says.

Juicing Your Fruit Bowl

"Fruits have more calories than vegetables so if you can't eat fresh fruit, eat canned fruit," Pataki says. "Juicing is not a bad thing either because it is easier to drink then chew when you don't feel well," she says.

"Generally I am opposed to juicing because it takes away fiber," adds Vagnini. "I'd prefer a person eat an apple or orange, but when you are debilitated it's a very good way to get in nutrient density, is easy to do, and more palpable."

Crunching Something Cruciferous

"I recommend one serving a day of cruciferous vegetables for optimal immune function," Beller says. Whether Brussels sprouts, cabbage, bok choy, broccoli, cauliflower, collard greens, radishes, broccoli sprouts, or others, cruciferous vegetables are probably one of the strongest powerhouses of phytochemicals or plant-based substances that are rich in disease fighting antioxidants, fiber, vitamins and minerals.

"They should be a key player in one's weekly -- if not daily -- nutrients," she says. Sneak them into a salad or a sandwich.

Other helpful appetite boosters include:

• Keep a food diary. "The first step is to keep a food diary or a careful food history for at least two weeks to help evaluate calories and nutrient intake better -- then show it to your doctor," Vagnini says. It also should include beverages and reflect how you feel after you eat, he says. Medications, too, should be included.
• Be wary of nutrient thieves. "Fast food is easy and cheap and can be double trouble," Vagnini says. "These foods contain higher amounts of fat, sugar, and salt and they rob the body of nutrition," he says. Steer clear!
• Eat smaller meals. "Eat small amounts often because most people can't manage the three-meal-a-day thing when they don't feel well," Pataky says. Even three normal meals seem like a lot to people who don't have an appetite. Also, get enough rest because people who are tired don't eat, and if you can, engage in some exercise such as walking. "Exercise improves appetite and fatigue," she says.