Optimum food intake depends on how many calories you need.
It is not always as simple as calories in versus calories out when it comes to weight, but if you consume more each day than you use up, you will usually put on weight. If you consume fewer calories than you need for energy, you will likely lose weight.
This article explains how much individuals should eat and what types of foods should be included in a healthy diet.
Here are some key points about how much food to eat. More detail and supporting information is in the main article.
- If you consume more calories than you burn off, you are likely to put on weight
- To lose weight, reducing calorie intake and increasing the number of calories you burn is essential
- It is important to eat a variety of natural foods to stay healthy
Daily calorie requirements
The amount of food a person should eat each day depends on a huge variety of factors.
How much you should eat depends on what your aims are. Do you want to maintain your body weight, lose or gain weight, or prepare for a sports event?
Any focus on food intake is closely linked with calorie consumption.
Calories are a measure of how much energy there is in the food we eat. Understanding calories helps us work out how much food we need to eat.
Different foods have a different number of calories per gram or ounce of weight.
Below are some general daily calorie requirements for males and females. A low active level means taking part in 30-60 minutes of moderate activity each day, such as walking at 3-4 miles per hour. Active level means at least 60 minutes of moderate activity each day.
Daily calorie requirement for males (Source: Health Canada):
|Age||Sedentary level||Low active level||Active level|
Daily calorie requirement for females:
|Age||Sedentary level||Low active level||Active level|
People aiming for a healthy body weight will need to check the calorie content of the food they eat so that they can compare how much they are burning against their consumption.
How much food do I need per day?
This section explains how much of each food type we should eat per day, such as fruit, vegetables, grains, milk, and meat, or alternatives to dairy or meat.
According to Health Canada, people should consume these recommended numbers of servings each day. For information on serving sizes, check the next section.
Age 2-3 years: Fruit and vegetables 4, Grains 3, Milk (and alternatives) 2, Meat (and alternatives) 1.
Age 4-8 years: Fruit and vegetables 5, Grains 4, Milk (and alternatives) 2, Meat (and alternatives) 1.
Age 9-13 years: Fruit and vegetables 6, Grains 6, Milk (and alternatives) 3-4, Meat (and alternatives) 1-2.
Age 14-18 years (male): Fruit and vegetables 8, Grains 7, Milk (and alternatives) 3-4, Meat (and alternatives) 3.
Age 14-18 years (female): Fruit and vegetables 7, Grains 6, Milk (and alternatives) 3-4, Meat (and alternatives) 2.
Age 19-50 years (male): Fruit and vegetables 8-10, Grains 8, Milk (and alternatives) 2, Meat or alternatives 3.
Age 19-50 years (female): Fruit and vegetables 7-8, Grains 6-7, Milk (and alternatives) 2, Meat (and alternatives) 2.
Age 51+ years (male): Fruit and vegetables 7, Grains 7, Milk (and alternatives) 3, Meat (and alternatives) 3.
Age 51+ years (female): Fruit and vegetables 7, Grains 6, Milk (and alternatives) 3, Meat (and alternatives) 3.
This is a reference amount to help us determine how much of the four groups of foods we should consume each day. Look at the examples below:
Half a regular-sized can of vegetables such as chickpeas constitutes one serving.
- Fruit and vegetables: 1 piece of fruit, half a cup of fruit juice, half a cup of canned or frozen fruit or vegetables, 1 cup of leafy raw vegetables or salad
- Grains: Half a bagel, 1 slice of bread, half a tortilla, half a pitta, half a cup of cooked couscous, rice or pasta, one ounce of cold cereal, three-quarters of a cup of hot cereal
- Milk and alternatives: 1 cup milk, 1 cup of soy drink, three-quarters of a cup of yogurt, 1 and a half ounces of cheese
- Meat and alternatives: 2 and a half ounces of cooked fish, lean meat, poultry or lean meat, 2 eggs, 2 tablespoons of peanut butter
Consuming fruit and vegetables: Experts say you should consume at least one dark green and one orange colored vegetable each day. Examples of dark green vegetables include spinach, kale, and broccoli.
Go for fruit and vegetables with either no sugar, salt, or fat, or at least as little as possible. It is recommended to steam, bake, or stir fry the vegetables. Limit or avoid foods that are deep fried. Whole fruit and vegetables are a better choice than their juices, as they provide more nutrients and fiber. They are also more filling which can deter overeating.
Consuming grains: Health authorities say we should aim for whole grains for at least half our grain consumption. Go for variety, including wild rice, quinoa, oats, brown rice, and barley. Whole grain pasta, oatmeal, and breads are better than those made from refined cereals.
A good grain should not have a high sugar, salt, or fat content. Alternatives to grains that contain many of the same nutrients are beans, legumes, quinoa, and starchy vegetables like sweet potatoes and peas.
Consuming milk (and alternatives): Consume 2 cups per day for good vitamin D and calcium intake. If you don't drink milk, have fortified drinks. Limit your intake of milk with added sugars and other sweeteners. Low-fat milk may be recommended if you are limiting your total fat or saturated fat intake for heart health reasons.
Meat and alternative: Make sure you are eating alternatives, such as tofu, lentils, and beans regularly. It is recommended to have fish at least twice a week. Beware of certain types of fish for mercury exposure. Opt for lean meats, such as chicken or turkey.
Rather than frying, try roasting, baking, or poaching. If you are eating processed or prepackaged meat, select low-salt and low-fat ones. Limit your overall intake of processed meats since you may have an increased risk for cancer with regular intake.
When eating carbohydrates, choose unrefined carbs, such as whole grains, which are high in fiber and release energy slowly, so that you feel full for longer.
Limit saturated fats and avoid trans fats as much as possible. It is recommended to consume not more than 10 percent of your total calories from saturated fat. Plant oils, fish, and nuts are the best sources.
Make sure to get plenty of fiber. When eating fruit and vegetables, eat a variety of colors. If you are not a great milk-drinker, make sure your consumption of calcium is adequate.
If your main concern is to know how much food you should eat, you still have to be aware of their calorie values. With high-calorie foods, the quantity will have to be less, while with lower-calorie ones you can eat more.
Severe calorie restriction
Some people claim that severely limiting daily calorie intake can extend overall lifespan.
Animal studies found that some species appear to live longer if they are partially starved, but the studies have been described as "poor quality," and it is not certain that restricting calories would have the same effect on humans.
However, scientists from Louisiana State University in Baton Rouge explained in the journal Nature, in 2012, that the two main factors that influence lifespan are good genes and a healthy, well-balanced diet.
The researchers believe that many previous studies were flawed, as they compared bad high-calorie diets with very-low-calorie bad diets. In other words, there was no control.
They explained that their 25-year study using rhesus monkeys on very-low-calorie diets did not help them live longer.
Meanwhile, findings from a study, published in the American Journal of Clinical Nutrition in 2013, suggest that if you eat your "five-a-day" portions of fruit and vegetables, you are likely to live longer.
In 2016, researchers concluded that diet's effects on aging "are not simply the result of the reduced amount of calories consumed, but are also determined by diet composition."