With the holidays upon us and New Year's Resolutions looming I thought I'd repost this one!
There are so many books and web sites out there saying there is some magic number for weight loss. We are all individuals and have different caloric requirements. If you eat too little your body will slow down your metabolism and you will not lose weight, if you eat too much you will gain weight. Below is a pretty easy formula which I have found extremely helpful.
Step 1 : How many calories do you need daily?
To calculate how many calories you need a day take your healthy weight (http://theworkoutshop.blogspot.com/2010/10/how-much-should-you-weigh.html), for me its 115 lbs and multiply by 10 calories/pound = 1150 calories. You then need to calculate in daily activity, if you are pretty sedentary, (work at a desk job) multiply your calories by 1.2 to 1.4, if you are moderately active (walk the dog, walk to work etc) multiply by 1.4 or 1.5, if you are very active (on your feet all day at work, do a lot of lifting etc) multiply by 1.6 to 1.8.
I'm moderately active during the day, I have a desk job but I walk the dog twice a day and walk to and from work so I usually multiply my 1150 calories by 1.5 giving me 1725 calories a day. This is the number of calories I can eat everyday and maintain my current weight.
This number does not include structured activities like going to the gym, kickboxing, biking etc, this is just an average day.
Step 2 : How many calories do you need to eat daily to lose weight?
There are 3500 calories in a pound, so you need to reduce your calories by 500 a day to lose 1 lb a week. It is recommended this is done with a reduction in calories consumed and an increase in calories burned (exercise).
Take your daily allotted calories (1725 for me) add any structured activities for the day.
Here is a useful site to calculate calories burned by activity
I will burn 350 calories at kickboxing, so today I have 1725 calories + 350 exercise calories for a total of 2075 calories. If I eat all 2075 calories I will maintain my weight. If my goal is to lose 1 pound a week I have to reduce my total calories by 500 calories daily and only consume 1575 calories. I calculate this number daily as my activities change day to day. It is not recommended to cut your calories by much more than 20% per day, you don't want to feel deprived only to over eat later or put your body into starvation mode.
NOTE: If you are significantly overweight you should calculate your calories based upon the difference between your current and healthy weights. Ie. If you are a 5'6" woman who currently weighs 225 pounds but should weigh 130-143lb you should calculate your calories on the weight in the middle, 182 pounds and adjust as you lose weight.
Step 3: How do you know how many calories you are eating?
There are a lot of great web sites available to track your daily caloric intake. I really like these in particular, they are free and easy to use:
If you like tracking your food intake in a journal (which I do) calorieking.com is a great site to find out how many calories are in the foods you are eating.
Remember weight loss is not about starving yourself, it is about making healthy lifestyle changes, being mindful of what you are eating and increasing your daily activity. It's always recommended to meet with a dietitian to go over your individual nutrient needs.
Reference: Sports Nutrition Guidebook by Nancy Clarke, MS, RD http://www.nancyclarkrd.com/