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Monday 15 August 2016

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What we should eat? Author Dr P K Gupta

The last one in the series of our requirement for food is the adequate calories.

Calories: What They Are and Why You Need Them

What calories are?

Calories are simply a measure of the energy in the foods that you eat. Your body doesn’t use energy to raise the temperature of water, but you need energy (measured as calories) to fuel all of your daily functions – your basic metabolic processes, as well as all the activity you engage in throughout the day. But in order for your body to tap into this energy, it first has to be released from the foods you eat.

 

Why we need calories?

Providing energy to the body is often compared to the way you provide energy to your car. When you put fuel in your car’s tank, there is energy (which, by the way, could also be measured in calories!) “locked up” in the gasoline. But just having gas in the gas tank isn’t enough to make the car move. In order for that to happen, the fuel has to be ignited in the engine, which releases the energy from the gasoline – energy that can be used to propel the car.

Similarly, the food (fuel) that you eat has energy – in the form of calories. These calories are absolutely necessary to life.   Your resting metabolic rate (the number of calories your body uses every day for the most basic processes just to keep you alive) accounts for about 75 percent of the calories your body uses every day. The remaining you burn during the day are used to fuel your muscles as you move around throughout your day and engage in exercise, and a very small amount that is used to digest and process your food.
What is the best source to meet requirements of calories?
The food (fuel) that you eat has energy. The “big three” macronutrients – protein, fat and carbohydrate – provide the majority of the calories we eat.
What is the estimated requirement of calories for our body?
Estimated amounts of calories needed to maintain energy balance for various gender and age groups at three different levels of physical activity are summarise in the table (vary depending upon age). Based on dietary intake data or evidence of public health problems, intake levels of the following nutrients may be of concern for:
Sedentary means a lifestyle that includes only the light physical activity associated with typical day-to-day life.
Moderately active means a lifestyle that includes physical activity equivalent to walking about 1.5 to 3 miles per day at 3 to 4 miles per hour, in addition to the light physical activity associated with typical day-to-day life
Active means a lifestyle that includes physical activity equivalent to walking more than 3 miles per day at 3 to 4 miles per hour, in addition to the light physical activity associated with typical day-to-day life.

Sedentary
Moderately Active
Active
Child 2-18 yrs
1000-1800
1200-2000
1200-2400
Female  19+ yrs
2000-1600
2200-1800
2400-2000
Male 19+ yrs
2400-2000
2600-2200
3000-2400/2800

How to calculate calories in a serving of food?
The food we eat has calories. A gram of protein has 4 calories’ worth of energy; a gram of carbohydrate also has 4 calories locked away. Fat is a more concentrated source of energy – each gram of fat contains 9 calories of energy. There’s one other calorie source that’s alcohol. A gram of pure alcohol has 7 calories, nearly as calorie dense as pure fat.
Which food you should avoid?
Let me say in brief
If you were to look at the nutrition facts panel on a serving of potato chips, it might say that the chips have 7 grams of fat, 17 grams of carbohydrate, and 2 grams of protein, and 140 calories.
Since fat has 9 calories per gram, the 7 grams of fat contribute 63 calories to the total; since carbohydrate has 4 calories per gram, the 17 grams of carbohydrate add another 68 calories; and the 2 grams of protein contribute just 8 calories. When you add up all the calories (63, 68 and 8) it totals 139 calories (nutrition facts panels are allowed to round their numbers).
Most foods contain calories from more than one source – with the exception of foods like oils (all fat calories) or sugars (all carbohydrate calories).
Whether calories are bad for you?
Calories aren't bad for you. Your body needs calories for energy. But eating too many calories — and not burning enough of them off through activity — can lead to weight gain. Most foods and drinks contain calories.

Key Recommendations for Specific Population Groups

  • Adults: calcium, potassium, fiber, magnesium, and vitamins A (as carotenoids), C, and E,
  • Children and adolescents: calcium, potassium, fiber, magnesium, and vitamin E,
  • Specific population groups (see below): vitamin B12, iron, folic acid, and vitamins E and D.
  • People over age 50. Consume vitamin B12 in its crystalline form (i.e., fortified foods or supplements).
  • Women of childbearing age who may become pregnant. Eat foods high in heme-iron and/or consume iron-rich plant foods or iron-fortified foods with an enhancer of iron absorption, such as vitamin C-rich foods.
  • Women of childbearing age who may become pregnant and those in the first trimester of pregnancy. Consume adequate synthetic folic acid daily (from fortified foods or supplements) in addition to food forms of folate from a varied diet.
  • Older adults, people with dark skin, and people exposed to insufficient ultraviolet band radiation (i.e., sunlight). Consume extra vitamin D from vitamin D-fortified foods and/or supplements.

What we should eat?

  • More dark green vegetables, orange vegetables, legumes, fruits, whole grains, and low-fat milk and milk products.

  • What we should avoid?


  • Less refined grains, total fats (especially cholesterol, and saturated and trans fats), added sugars, and calories.

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