Weight Maintenance Walkthrough: Step One

Now that the holidays are winding down, I'm sure many of us are thinking about repentance when it comes to our eating and exercise habits. I'm one of them. You may be looking to lose weight or just keep from gaining more weight. I'm looking to slow my weight gain with my pregnancy.

I thought I'd share my personal approach and tools I use for weight maintenance. There is a lot of information to share, so I will be doing it in a series of  posts.

Step One: Determine how many calories you should be eating (as accurately as you can).

 
Why? People are really good at overestimated our calorie needs. I do it too. I always seem to forget what I've calculated many times in the past so I have to calculate it again. It's more than a good idea to know how many calories you need to eat to maintain or lose weight--it's essential. Weight loss isn't magic, it's math. However, without hooking you up to a machine 24/7, it's impossible to know exactly how many calories you need, so we do our best to estimate as accurately as we can. 

 CAUTION: If you search "calorie calculator" online, you will find pages of websites offering calculators where you just enter your height, weight, gender, age and activity level. If you were to enter your information into multiple websites, you would get multiple values, sometimes drastically different. I did a little test and tried about 10 different online calculators and got values ranging from about 1900 calories all the way up to 2700 calories. This leads me to believe many of these calculators aren't very user friendly or maybe just not very accurate--it's hard to tell without knowing exactly how they are calculating calorie needs.   

 For that reason, I think it's helpful to understand how calorie needs are calculated so you are more sure to get an accurate number.

The most commonly used formula to calculate calorie needs is called the Harris Benedict formula.

Men	BMR = 88.362 + (13.397 x weight in kg) + (4.799 x height in cm) - (5.677 x age in years)
Women	BMR = 447.593 + (9.247 x weight in kg) + (3.098 x height in cm) - (4.330 x age in years)

These formulas, one for men and one for women, calculate the Basal Metabolic Rate (BMR) which is how many calories it takes to keep you alive if you were just laying still all day long doing absolutely nothing else. If you calculate your BMR, it will feel like a really low number, something like 1300 calories for example.

To apply this to a real person that walks around, cleans their houses and plays basketball on Wednesadys, we multiply the BMR by something called an activity factor. The more active a person is, the the larger the factor.

Little to no exercise	Daily kilocalories needed = BMR x 1.2
Light exercise (1–3 days per week)	Daily kilocalories needed = BMR x 1.375
Moderate exercise (3–5 days per week)	Daily kilocalories needed = BMR x 1.55
Heavy exercise (6–7 days per week)	Daily kilocalories needed = BMR x 1.725
Very heavy exercise (twice per day, extra heavy workouts)	Daily kilocalories needed = BMR x 1.9

I believe this is where much of the variation in the online calculators come from--how they calculate activity level. Different websites describe activity levels in different ways--it's hard to know if you qualify for "moderate exercise" or "light exercise". I personally don't like how this is done. It's confusing. It leaves lots of room for interpreting it differently and therefore room for error.

MY WORK AROUND: I always calculate my own calorie needs as being sedentary so I don't overestimate my calorie needs. I use this as a starting point to make decisions on how many calories I'm going to need to burn exercising, how many calories I am going to aim to eat (see Step 2 next post). The CDC says about 80% of adults don't get the recommended level of exercise so I'd say "sedentary" is an accurate estimation for most people anyway.

To calculate your BMR, I trust the calculators at Runner's World and this website. Multiply your BMR by 1.2 (Runner's World does it for you). This is your baseline, how many calories you burn in a day without exercising. 

To use myself as an example:

My BMR = 1600 calories
1600 calories x 1.2 = 1920 calories
My baseline= 1920 calories

CAUTION: The Harris Benedict equation has a fatal flaw--it overestimates calorie needs for very overweight and obese people. For obese people, the formula cannot account for what part of your extra body weight comes from muscle (requires energy) and what comes from fat. In order to avoid overestimating your calorie needs if you are very overweight or obese, some experts recommend taking the average of your current weight and your ideal body weight* and use that number

Example:  
Current weight: 250 lbs
Ideal Body Weight: 170 lbs
Use this weight:  210.

Other experts say to just use your ideal body weight. Personally, I prefer to use your ideal body weight, or at least your goal weight. There's a saying that goes something like "If you want to weigh 140 lbs, then eat like you only weigh 140 lbs."

*Ideal body weight is a healthy weight for your height and body type. BMI is just one of the ways to estimate a healthy body weight and happens to be the easiest to use.



Now that you have a baseline of how many calories you need (if you did no exercise), my next post I'll talk about how you can make goals and come up with a plan for how much you are going to eat and exercise each day.