2 Mar 2012

Recommended daily calorie intake


Daily calorie intake for men and women


Now that you know what calories are and you know how to figure out how many are in your food … you just need to know how many you should be eating.


The average recommendations vary a little. In England, the government suggests these figures for people maintaining their weight:


2500 calories a day for men
2000 calories a day for women (2,500 in third trimester of pregnancy)
1800 calories a day for children aged 5-10
However, the government are reviewing their advice – especially because most of us have sedentary jobs – as they suspect the daily caloric requirement for the average person is actually lower than this.


What’s my personal daily calorie recommendation?


To be certain that you’re eating the right amount, you should calculate your personal recommended calorie intake. We all have different energy needs, and your daily calorie requirement is determined by three main factors:
  • Your weight
  • The amount of muscle you have
  • Your activity levels
Your weight matters because you burn up calories just to keep your body going. The heavier you are, the more calories you need. And your muscle mass is also important: a pound of muscle may burn up to an extra 50 calories per day, compared with a pound of fat.


Finally, your activity levels need to be taken into account: someone working on a building site and hitting the gym for hours at the weekend will be burning off many more calories than those of us with desk jobs…


So, if you want to come up with your personal calorie requirement, there’s a formula used by nutritionists and sports professionals. You might want to grab a calculator at this point… I’ve given the formula for both imperial and metric units.


Adult women:
655 + (4.3 x weight in pounds) + (4.7 x height in inches) – (4.7 x age in years)
OR
655 + (9.6 x weight in kg) + (1.8 x height in cm) – (4.7 x age in yrs)


Adult men:
66 + (6.3 x weight in pounds) + (12.9 x height in inches) – (6.8 x age in years)
OR
66 + (13.7 x weight in kg) + (5.0 x height in cm) – (6.8 x age in yrs)


This formula gives your BMR – your Basal Metabolic Rate (this is how many calories you’d use if you spent the whole day lying in bed…)


You now need to multiply your result by a percentage to reflect your activity level. Some people prefer to use the lowest level and then use a Heart Rate Monitor (HRM) or the readout from machines at the gym to work out more accurately how many calories they’re burning from exercise. Note that all levels include daily activities like gentle walking and light housework – when “exercise” is mentioned, it is in addition to this, eg. a workout, gym class, or jog.


Sedentary (no exercise, sit at a desk most of the day): BMR x 120 percent (ie. an extra 20% on top of the BMR)
Light Activity (no exercise, on feet during the day, eg. shop work): BMR x 130 percent
Moderately Active (exercise 3 or more days a week for 30 minutes or more): BMR x 140 percent
Highly Active (exercise 5 or more days a week for 30 minutes or more): BMR x 150 percent


The result now gives you how many calories you need to maintain your current weight.


Note that to multiply the BMR by 100%, you multiply it by 1; so to multiply by 140% you multiply by 1.4.





Here’s an example: John is a technical writer, 35 years old, 5’ 11” tall and weighs 200lbs (about 40lbs overweight). He cycles to work most days.


66 + (6.3 x weight in pounds) + (12.9 x height in inches) – (6.8 x age in years)


= 66 + (6.3 x 200) + (12.9 x 71) – (6.8 x 35)


= 66 + 1200 + 915.9 – 238


= 1943.9 (BMR)


Now multiply by 1.4 = 2721.46


So, to maintain his current weight, John should eat about 2700 calories per day.


But I want to lose weight – how many calories should I eat for weight loss?


To lose 1 lb (0.45kg) of body weight, you need to under-eat by 3,500 calories. Obviously you can’t do that in a day, but over the course of a week, it means cutting your daily intake by 500 calories – an achievable amount for most of us. If you have a lot of weight to lose (especially if you’re currently over-eating and gaining weight), you could cut back by 1,000 calories per day and lose 2 lbs (0.9kg) a week.


So, taking the example of John above, he would need to cut down from his maintenance calories of 2700 per day to a “diet” level of 2200 per day if he wants to lose a pound a week. That would mean losing those extra 40lbs in under a year. If John wanted to lose weight more quickly, he could cut calories to 1700 per day.


Note that you should not drop below 1,000 calories per day (and many nutritionists recommend not going beneath 1,100 or 1,200 calories). It can be tempting, especially if you’re small or don’t have much weight to lose, to eat as little as possible – but this will have negative effects on your body and your metabolism, making it harder for you to stay slim in the future.





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