Finding your stable daily calories can be a bit daunting. There are all kinds of different measures out there, they often disagree, and we often aren’t sure what our activity levels are according to the calculations. A scientific test can be done, but they are expensive and not very widely offered. But there is an easy answer- take your best guess, track your calories, and compare the results. Try different formulas and use the one that is the best match!
When I started my diet a year ago, I used a calculation that said my stable daily calories were 2300. Imagine my surprise when I lost 5 lbs eating 2350 calories on average! As my diet theory was to track and adjust my behaviour based on a constant feedback loop, I didn’t mind the 2350 vs 2300, and learning that 2300 was so very wrong was a huge benefit.
I then tried a number of different stable calorie equations (= basal metabolic rate(BMR) + activity calories) and found one that matched- the Harris-Benedict and a surprising admission that I wasn’t as sedentary as I thought. Coaching soccer and running after 3 kids must add up.
Then came my plateau. It was after Christmas, and I ate 2300 calories per day on average for all of January, taking a slow road back into my diet after Christmas fun. And lost no weight. Where was my weight loss? Had my body metabolically revolted against weight loss? Had I lost excessive lean muscle mass having dropped 20 lbs in 6 months? What was going on?
I adjusted my stable daily calories to match my weight loss (none!) and continued on through February, striving for a new deficit based on my experimentally determined stable daily calorie rate.
Now calories in matched my weight loss again! But I still wondered what happened, and so I finally got a round to doing the numbers again.
Diet Start- Harris-Benedict
Age: 39, Weight: 235, Height: 6 feet,
Activity Level: moderate 3 times per week.
DAILY STABLE CALORIES = 3006
Now remember, another website had said 2300! That’s a big difference. I had started trying to diet at 1600 per day, for a 700 deficit, but it was too much, I landed at 2350, and still lost weight. Then I did more experimenting with different formulas and found a good fit.
But now my daily stable calories were 2540 based on my January weight loss. What was going on? Well, three things had changed- I had lost 20 lbs, I was doing less activity in the winter, and I had aged, turning 40. Running the Harris-Benedict equation with these three changes:
Diet @ 6months- Harris-Benedict
Age: 40, Weight: 220, Height: 6 feet,
Activity Level: low/none
DAILY STABLE CALORIES = 2503
Wow. I needed 503 calories per day less then last summer. And here I thought I had gotten better at managing my diet discipline and improving my calorie deficits. And this was almost a perfect fit for my experimentally calculated 2540.
Lets see what happens approximately 1 month later with weight loss based on this new stable rate:
Diet @ 7months- Harris-Benedict
Age: 40, Weight: 211, Height: 6 feet,
Activity Level: low/none
DAILY STABLE CALORIES = 2435
The weight loss matched my calorie intake to within .2 pounds. But wow! Another 70 calories less. After another couple of months, there will be a huge impact here. Even 70 is pretty huge: 70 * 365 days / 3500 calories/lb = 7lbs a year. Another month, and 140 cals would be roughly 14 lbs a year in wieght loss opportunity lost, and possibly the impression of a new plateau.
Now what happens when my activity level increases with the warmer weather…
Diet @ 6months- Harris-Benedict
Age: 40, Weight: 220, Height: 6 feet,
Activity Level: moderate 3 times per week
DAILY STABLE CALORIES = 2790
Up 300 calories. But still 216 calories less then six months ago. So in six months, by virtue of weight loss and age alone, I need 200 calories less per day. That’s 6000 calories- almost 2 lbs – a month of weight loss that I would be expecting and not getting if this went unnoticed. Over a year, that’s 73000 calories and 20 lbs. This is weight loss I would have been expecting, but not finding due to the impact of lost weight.
With less activity, I was missing 500cal/day of weight loss. Assuming I never noticed, I would have 1) stopped losing weight, and 2) missed the opportunity for 52 lbs of weight loss in a year if I had adjusted and maintained a similar calorie deficit (assuming I had 52 left to go- it’s actually 31- but it does mean hitting my goal in the middle of the summer versus at Christmas).
Not only have I learned this by tracking my weight versus calories for the last six months, but I know it to be accurate. My predicted weight loss in the last 2 months versus my calorie deficit estimate (with the correct numbers) match to within 1/4 of a pound. That’s on 10 lbs lost. This means I trust I will see progress over the next 6 months so long as I stay aware and mindful of my eating inputs.
My recommendation- run the numbers over your expected/desired milestones in the next 6 months and year. What is the impact of 20, 30, and 40 lbs lost. Then pay attention- that plateau you are seeing may just be an illusion.
And by learning your true stable daily calorie rate, and gaining a sense of trust generated by an effective awareness and feedback mechanism, you will have a tool lets you know, in no uncertain terms, that you will be successful.
