I’ve made the case that weight loss is all about calories, and I’ve shown you how to use simple math to calculate how many calories you should be consuming in order to reach a particular weekly weight loss goal.
That’s the easy part. The hard part is motivation: how do you keep yourself from straying off the path or failing altogether? The difficulty in any attempt to develop a disciplined habit is you…your weaknesses, your cravings, your circumstances, etc. You need to know yourself well enough to recognize your problem areas, and be committed enough to develop strategies to deal with those problems. If you don’t, there’s likely a brick wall in your near future with “FAIL” spray-painted across it in bold letters.
But before we get into the subject of motivation, I want to answer a few questions some of you have about the mechanics of weight loss. If you’re not absolutely certain that monitoring your calories will result in you reaching your goal weight, you’re going to falter when obstacles and challenges inevitably come.
Question #1: “Is my goal weight realistic?”
You don’t have to guess what your weight should be; your goal weight is based on what your body fat percentage should be. An acceptable body fat percentage is going to range from the lean side of athletic to the upper limit of what the medical community has determined is healthy. For women, that range is 14% to 31%. For men, the range is 6% to 24%.
Next, we need to calculate your lean body mass (muscle). Let’s say you are a female, you weigh 168 pounds, and your current body fat percentage is 38%. That would mean that your lean body mass would be 62% (100% – 38%), or 104 pounds (62% of 168 pounds).
Finally, we calculate your goal weight using your lean body mass and the range of healthy body fat values listed above. To do that, we would divide your current lean body mass in pounds by your desired lean body mass percentage (in decimal form). The range of healthy body fat values is going to produce a pretty wide range of “ideal” weights, so to be more helpful, let’s just say that our 168 pound example woman wants to be athletic. Knowing that, we can advise her to shoot for a body fat range of about 18-22% (these are approximates). We would calculate her desired lean body mass percentages by subtracting 18 and 22% from 100%, giving us values of 78% and 82% respectively. Then we’d divide her current lean body mass by .78 and .82:
104 pounds divided by .82 = 127 pounds, and 104 pounds divided by .78 = 133 pounds. Her goal weight range is going to be between 127 and 133 pounds.
Subtract that from her current weight of 168 pounds, and you’ll find that she needs to lose between 35 and 41 pounds. Divide those numbers by 1.5 pounds per week, and you find that it will take her 23 to 27 weeks to reach her goal, or about 6 months.
Question #2: “How many calories am I really burning with the exercise I’m doing?”
When we first start you on a weight loss program, we generally just calculate your BMR, multiply it by an “activity factor” (covering the spectrum from sedentary to very active), and arrive at a number of calories your body is burning on a daily basis. This is usually pretty accurate, but as you weigh in week after week, you may notice that you’re not hitting your weight loss goals as expected. If that’s the case, it’s because you’re either not consuming the number of calories you think you are, or your activities are not burning the calories you think they are.
For example, let’s say that our calculations say that you should be losing 1.5 pounds per week, but you are consistently losing only three quarters of a pound per week. Since we know that 3500 calories is equal to one pound, we know that in order to meet your weekly weight loss goal that you will either need to burn another 375 calories per day, or consume 375 fewer calories per day (or some combination thereof). If we’re going to subtract it from your diet, you journal what you’re eating and we go through the list and assign calorie values, and then see where we can take it out. If you’re going to increase your exercise, you can find a useful chart that shows calorie expenditures for various activities, and then make your changes from there. Here’s a link to a good chart: http://tinyurl.com/94ym7
Question #3: “How come I’ve sometimes gained or lost 5 pounds in a week if most people can only realistically average 1 to 2 pounds of weight loss per week”?
Let’s review the math. If you lost 5 pounds of fat in one week, it would mean that you burned 17,500 more calories than you consumed that week, which breaks down to burning about 2500 more calories than you consume on a daily basis. A typical woman is going to have a BMR of maybe 1500 or so. If she is really, really (really) active, she will burn a total of about 2850 calories per day (BMR plus activities). Do you see where this is going? The math says that she would have to train like a crazy woman and consume only 350 calories per day, which would not produce the energy and nutrition she would need to train at anywhere near that level.
It is possible for a very obese person who is taking in the minimally healthy number of calories and is training at a very high level to lose 5 pounds of fat in a week, but the most likely reason for weight loss of more than 2 pounds or so is that you’ve actually lost a combination of body fat and water. That’s why your 5 pounds of weight loss one week is followed by 1-2 pounds in successive weeks.
I tell you this because you need to pay attention to body water when you have a big decrease or increase in body weight over the space of a week. You’re not going to gain 5 pounds of fat even if you ate an entire Pizza Hut Meat Lover’s pizza all by yourself! You’d likely gain less than a pound…and the rest of the new weight on the scale is body water retained due to your high sodium pizza adventure.
So that answers the questions. Next time, we start getting into motivation: how do we save you from yourself?
