At 5'10, 160lbs I was an athletic build. After I started rock climbing 6 months ago (4 hrs every other day with hard training ie sit ups, push ups, campus board...) I jumped to 170lbs in the first month with noticeable muscle mass increase. In the past three months I am down to 155lbs with visible abs and even more muscle definition/mass.

This prompted me to take a look at my caloric intake vs output and I found soemthing that may be of concern. According to many online calculators they gave me a result of 3800-4200 calories burned for 1 hr hard cycling per day and 4hrs rock climbing with training and all the normal daily tasks like walking.

After inputting the food I eat( all extremely healthy, no processed, almost gluten free and vegan except for eggs), the calculators say I consume 1600 calories!

What are the ramifications of having such a low intake to output ratio? Can this be sustained? If not how does one fix this?


You could experience:

  • lack of energy/motivation or general fatigue
  • muscle/strength loss
  • hormone imbalance/low testosterone

There are two fixes which come to mind:

  1. decrease activity level (# of days of activity or # of hours per session)
  2. increase cals to around maintenance (+200 or -200 should be a good range)

Personally #2 sounds like the more attractive option, it's not that hard (even for a vegan) if you add in extra virgin olive oil, nuts/seeds, avocados, almond/coconut milk, and by drinking a caloric sports drink during training.

Don't rely too heavily on the online calculator, just do a weekly weigh-in (preferably at the same time of day, e.g. first thing in the morning), see what the difference is, adjust what you're eating accordingly.

Be patient and pay close attention to how you feel; it may take a while to find the right energy balance to support your level of activity.

  • Thanks for the answer I like your suggestion about the daily weigh in I will definitely start that. And yes I think increasing my caloric is the way to go, I commute via bicycle and love climbing too much to reduce it!
    – AM_Hawk
    Feb 27 '14 at 16:25
  • Weekly weigh-ins. Day-to-day fluctuations are too short term and are affected too much by water retention. Weekly (or even every two weeks) would give a better idea of muscle+fat gains/losses.
    – riqitang
    Feb 27 '14 at 16:40
  • Yeah, a weekly or biweekly weigh-ins are recommended; daily fluctuations will just drive you nuts. Feb 27 '14 at 16:53
  • I agree about daily fluctuations. Yet I think I wouldn't manage to get a habit from it doing it only once a week. I put my weight in WeightBot on my phone everyday, and if I miss a day or two, the graph can still average out the missing data. Also, overall, the data will be more reliable; if somehow the one day of the week you decide to weigh yourself leads to an "inaccurate value", it will take 2-3 weeks before you realize it, 4-7 values averaged for one week is best IMHO.
    – Max
    Mar 5 '14 at 19:38

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.