Lean Me

Pop quiz (with a trick question): Your diet program says you have 200 Calories remaining in your energy budget today. You then spend 200 Calories exercising. How many Calories now remain in your energy budget for the day? The obvious answer is 400, and that’s the answer you’ll get from other diet tracking applications, but is it the best answer?

First, let’s think about how your total daily energy budget is calculated. We can roughly break your energy needs down into three components: 1. The energy you need to be alive, awake, in bed, which is called your basal metabolic rate, or BMR. 2. The energy you need to get through your daily life, including work, child care, etc. 3. The energy you use for exercise. For convenience, let’s refer to the total as your Required Daily Energy, or RDE.

Now, you could simply set a static energy budget for each day, such as RDE – 500 Calories if you wanted to lose weight. In fact, this is the most common approach, and explains the simple answer above. But is a 500 Calorie deficit to somebody with an RDE of 1200 Calories the same as a 500 Calorie deficit to somebody with an RDE of 3000 Calories? Of course not, and by definition the very act of exercising changes your RDE dynamically, which is why it is more effective to set your energy budget as a percentage of RDE.

Now let’s assume you want a 20% energy deficit (to lose weight) and revisit the question above. If you performed 200 Calories of exercise, that means your RDE must have increased by 200 Calories. Since you want to maintain a 20% deficit, that means you can eat 200 x 80% = 160 more Calories, bringing your remaining energy budget from 200 to 360, not 400. This is precisely how Lean Me’s adaptive mode functions. The exercise you track in Lean Me is exercise that counts, or at least exercise that actually gets counted.