A diet is a style of eating. People follow specific diets to improve their health, whether by losing weight, lowering their blood pressure, preventing diseases such as cancer or type 2 diabetes, or achieving other goals.
Some people eat a certain way to manage a health condition. For example, people with diabetes adjust the type and amount of carbohydrates they eat to avoid raising their blood sugar levels.
People with the celiac illness have to avoid wheat protein, gluten because eating them will inflame their intestines and make them sick.
ELEMENTS OF A HEALTHY DIET
No one diet is suitable for everyone. In general, a healthy diet includes high-quality, minimally processed foods such as fruits, vegetables, whole grains, low-fat dairy, and lean sources of protein.
It limits or avoids added sugar, salt, saturated and trans fats, and cholesterol.
According to the U.S. government’s Office of Disease Prevention and Health Promotion, most Americans do not follow this healthy eating pattern.
About three-quarters of the population does not eat enough fruit, vegetables, and dairy foods. Most Americans eat more than the recommended amounts of added sugar, salt, and saturated fat.
The U.S. Department of Agriculture offers an easy visual guide called MyPlate to encourage Americans to eat the right proportion of healthy foods at each meal.
The recommended plate comprises one-quarter of fruits, one-quarter vegetables, one-quarter whole grains, and one-quarter lean protein.
For weight management, portion sizes and calories are also significant. It can be challenging to determine how much you need to eat just by looking at a plate of food.
This is particularly true in restaurants, where the typical portion sizes are much larger than the number of food doctors, and nutritionists recommend eating.
Checking the nutrition facts label on the packaged foods you buy will help you determine the correct serving sizes.
For example, a serving size of ice cream is just 2/3 cup, or one small scoop–much smaller than many of the portions served in restaurants and ice cream shops.
Cutting restaurant meals in half or sharing them is another strategy to help you avoid overeating.
In general, calorie needs range from 1,600 to 2,400 calories a day for an adult woman and 2,000 to 3,000 calories daily for an adult man.
However, the exact number of calories you need to eat daily depends on your age, weight, gender, activity level, and other factors.
For example, an active 200-pound man will need to eat more calories than an inactive 135-pound woman.
The following are some of the most popular and well-studied diets for health promotion.
REDUCED-CALORIE OR LOW-FAT DIET
If you are striving to shed weight, you need to burn more calories than you take in.
To achieve a healthy weight-loss goal of .5 to 2 pounds a week, you would need to cut about 500 to 750 calories daily.
You can do this by eating more foods that are lower in calories (such as fruits and vegetables), eating fewer high-calorie foods (such as sweets and fried foods), and reducing your portion sizes.
Low-calorie diets can vary in their recommendations. Some are very restrictive. Extremely low-calorie diets recommend as few as 500 calories per day.
Doctors advise that women do not eat fewer than 1,200 calories a day and that men do not eat fewer than 1,800 calories a day.
Going below these calorie counts without your doctor’s advice could lead to malnourishment or dangerously rapid weight loss.
Cutting fat is another way to improve your health and lose weight. In general, high-fat foods contain more calories than do low-fat foods.
Many high-fat foods, such as fried foods and baked goods, are also unhealthy. In general, any food that has 3 grams or less of fat per 100 calories is considered low fat.
The Mediterranean diet originated in countries ringing the Mediterranean Sea, including Greece, Spain, Italy, and France.
It includes abundant foods in those areas—fruits, vegetables, fish, whole grains, nuts, olive oil, and red wine. It limits red meat, cheese, and added sugar.
Studies have linked the Mediterranean diet to a variety of health benefits, including:
- reduced risk for heart disease
- lower low-density lipoprotein (LDL) cholesterol
- a lower risk for certain types of cancer
- protection against Parkinson’s and Alzheimer’s disease
VEGETARIAN OR VEGAN DIET
A vegetarian diet excludes meat, poultry, fish, and many other animal-based products. Some vegetarians do eat eggs, cheese, butter, and milk.
Vegans will not eat any foods taken from animals. They rely solely on plant-based foods, getting their protein instead of soy, nuts, and seeds.
Vegans might need to take supplements to get nutrients predominantly from animal sources, such as vitamin B12.
Vegetarian and vegan diets may be helpful for weight loss. There is also some evidence that a plant-based diet can reduce the risk for heart illness, type 2 diabetes, hypertension, and certain types of cancer.
The Dietary Approaches to Stop Hypertension, or DASH diet is specifically designed to help lower blood pressure.
It is based on research from the National Heart, Lung, and Blood Institute (NHLBI).
This diet is high in fruits, vegetables, whole grains, fat-free or low-fat dairy, fish, poultry, beans, nuts, and vegetable oils.
It limits added salt, sugar, and saturated fat from red meat, coconut oil, and full-fat dairy products.
On top of lowering blood pressure, the DASH diet can help prevent diseases such as cancer, diabetes, and heart disease. It may also help you lose weight.
Some diets serve the purpose of treating or preventing disease. A person might go on a therapeutic diet to regain the weight they have lost, bring down their blood pressure or cholesterol levels, or prevent malnutrition.
Typically, a doctor and dietitian will oversee these plans. Examples of therapeutic diets include:
- low-sodium diet for heart disease or high blood pressure
- low-carbohydrate diet for diabetes
- high-fiber diet for bowel disease
- a high-protein diet for malnutrition
- dairy- or gluten-free diet for food allergy
Several diets purport to help you lose weight through extreme measures, such as by avoiding entire groups of foods (such as carbohydrates or fat),
eating only one type of food (such as grapefruit or cabbage), or severely restricting calories (fewer than 800 calories daily).
These types of programs, sometimes called fad diets, may not produce the results you want, leading to nutrient deficiencies.
Any diet you choose should include various foods from several different food groups and incorporate multiple nutrients.
It would help if you ate some fat (about 30 percent of your daily calories) and carbohydrates, which you need to fuel your body.
STARTING ON A DIET PLAN
One way to ensure that the diet you choose is healthy and appropriate is to work with a dietitian.
If you have a health condition, also consult with your doctor before starting any new diet plan.
Choosing a natural diet will improve your odds of success. If you are constantly hungry or missing your favorite foods, you will be more likely not to follow the new diet.
Be sure that you eat enough calories to prevent you from getting hungry, and let yourself enjoy your favorite foods occasionally.
“Diets that Work.” Hormone Health Network. July 2018. https://www.hormone.org/diseases-and-conditions/obesity-and-weight-management/weight-loss/diets-that-work (accessed December 10, 2018).
“Healthy Eating Plan.” National Heart, Lung, and Blood Institute. https://www.nhlbi.nih.gov/health/educational/lose_wt/eat/calories.htm (accessed December 10, 2018).
“Weight loss: Choosing a diet that’s right for you.” Mayo Clinic. July 3, 2018. https://www.mayoclinic.org/healthy-lifestyle/weight-loss/in-depth/weight-loss/art-20048466 (accessed December 10, 2018).
Academy of Nutrition and Dietetics, 120 South Riverside Plaza, Suite 2190, Chicago, IL, 60606-6995, (800) 877-0877, (202) 775-8277, https://www.eatright.org .