Today’s question is about calculating calorie needs, Basal Metabolic Rate (BMR,) and (gasp!) starvation mode…

Hey Coach,

I have been working to lose some weight and done some research in it but am a little confused on calculating my caloric needs. I checked several sites to determine my BMR which I averaged together to be around 2100 calories a day. This has been working for me for the most part but I am also exercising 4 days of a week on a stationary bike. Lately, the bike is telling me I am burning approx. 800 calories per session. I was told that I have to be careful that I do not try to burn or eliminate too many calories in one day or my body will go into a starvation mode and halt weight loss. The advice I was given was to not exceed a 750 calories deficit through diet and exercise in any given day.

So far I have lost 10 lbs since January which I am happy about but when going back to those same websites to see if I needed to adjust down my BMR slightly to account for my weight loss I started seeing additional calculators that factored in a persons activity level.

If I understand what I am reading, I need 2100 calories because I am alive and 400 more calories because of my activities combining to a total of 2500 calories per day. On days I am not exercising I have been sticking with my 2100 calories (potentially eliminating 400 calories for the day or just breaking even) but on exercise days I was not increasing it at all thus potentially eliminating 1200 calories which would put me over the limit and cause my body to go into starvation mode.

At the end of the day I just need to know if I should be eating 2100 a day or 2500 a day to break even for the day and then I can adjust up or down when I exercise.

I am 6′ 2″, 220 lbs, 34 years old, male, and lead a fairly sedentary lifestyle. My goal is to weigh 200 by June when I go in for my next physical. This probably may not seem like all that lofty of a goal but I have not weighed 200 lbs since entering 7th grade. No joke.


Caloric Calvin

Hi Calvin,

Congratulations on your weight loss so far and for sticking with it despite being bombarded with lots of numbers and math problems!

For everyone else reading this, let’s do a quick review:

  • Calvin wants to lose weight.
  • Calvin trains on a stationary bike.
  • Calvin is worried about his daily caloric needs.

The first thing we need to address are the calorie estimates, whether they’re from an online BMR calculator or the display of an exercise machine. The key word there is estimates. These numbers are fine for establishing a starting point, but that’s all. As much as I like sites like MyFitnessPal to track diet and exercise, their numbers are just estimates, too.

So what do you do?

If you really want to know your BMR, you could find a doc who does respiratory calorimetry testing. I’ve never had this done, but I believe it’s a sort of breathing apparatus that measures heat and/or gas exchange in your breath, which then determines what your BMR actually is.

That’s great, but we can save time and money by using a more practical method: pick a number, track results, and make adjustments. It’s that simple.

To set a minimum daily caloric intake for an athlete, I would generally go with a “bodyweight x 10” approach, putting you at 2200 calories per day, right around your current estimate. You can add extra calories to fuel your cardio workouts as necessary. (2100 vs 2500 calories per day, when you’re talking estimates, really isn’t a big difference, so anywhere in there is a fine starting point.)

Then you go about your business for a week or so and evaluate. If you’re not making progress, chances are your numbers are off. No big deal, that’s expected! You simply make a change, keep tracking, and re-evaluate as necessary.

So my short answer would be, “go with 2200 calories per day as a baseline and see what happens, then adjust as necessary.”

My slightly longer answer would add, “… making sure you’re also eating healthy, because doing nothing but limiting calorie intake is not a long term solution.”

Finally, my shameless self-promotional answer would add, “hire a coach to analyze your diet or create a custom meal plan to help you reach your goals.”


Coach Levi

P.S. Don’t worry too much about starvation mode, especially on a day-to-day basis. The studies that show any real difference in metabolic rate on a “starvation diet” are measured in terms of weeks, months, or years. The Minnesota Starvation Experiment, for example, included a 6-month starvation phase!

In general, you can maintain a reasonably high metabolism on a low-calorie diet with a weekly endurance eating day.


Is Fat Loss Your Goal?

I highly recommend watching this totally FREE 5-part video series from Dr. John Berardi, one of the sharpest minds in sports nutrition and fat loss.

pn fat loss video

Just click play!

You may also like

Leave a Reply