OR *Percent Daily Values based on a 2,000 Calorie diet.
This summer and fall I have been biking a lot to work. On days that I bike, according to different computer functions based off my weight, speed, and heart rate, I burn 1,200 to 1,400 addtional Calories.
It is pretty clear how my macronutrient needs change. I feel hungrier and eat more food. But how do my micronutrient (vitamins and minerals) needs change based on this increased output? Do they scale linearally? Assuming on days where I don’t work out I burn 2,000 calories and require 400 IU of vitamin D, on days where I work out and burn 3,200 calories, do I require (3,200/2,000)*400 IU of vitamin D? Or because the additional metabolic output is most concentrated in skeletal muscle contractions, do the additional needs vary across different micronutrients? Could the requirements of certain nutrients double or triple from a 50%-60% increase of Calorie burning because they are heavily used in maintenance of muscles or aerobic metabolism while others increase hardly at all because they are regular housekeeping nutrients that aren’t needed by muscles all that much? Has any research been done on this?
Man, I wish I could cite the study/article, but key nutrients show an amazing ability to maintain a great % of their max for surprisingly long times. I believe it was in research about fasting and/or in research over the effectiveness/need for multivitamins in athletes who burn many calories.
Yeah, I get that you don’t necessarily need to get 400 IU of vitamin D every single day to not be deficient, it just needs to average out to that. So you can 800 one day and 300 the next and 0 the next and 500 the next or whatever. The same is true of macronutrients: we can store up food as fat or glycogen. But we still need to keep up with changes in our caloric needs through dietary changes if we want to maintain the same weight.
However, presumably, the recommend daily consumption of micronutrients are based on long term averages of how much a person uses up of each nutrient each day. That is what I am curious about.
As an explanation: I recently had a physical where my blood was tested for vitamin D levels and I was judged deficient and placed on a perscription vitamin D supplement. I wonder if my extra working out this summer contributed to the problem? I obviously ate more food, but I don’t think I ate a balanced additional amount of food. My former intake of vitamin D was sufficient for a largely sedentary existance, but when it didn’t go up as I got moving was I chipping away at my supply? And by how much?
It will depend. Some vitamins and minerals play a part in digestion (macro or micro) so if you eat more because you burn more, you will also need more of those.
Others like Vitamin A for your eyesight at night - well, when the stores of the little receptors are full, they won’t get emptied faster because you bike, so that amount will stay pretty much the same.
In addition, some food components may block resorption of other parts. So if you changed your diet instead of just doubling portions, that might be why you have lower levels now.
I only know of this in the other direction, when going on a diet: doctors dislike FdH (Eat Half), because if you halve all your portions, you might not get enough vitamins and minerals. Instead, you’re supposed to leave a big part of meat and potatoes away, but eat the same portion of veggies.
The ideal diet is always a balanced one with lots of veggies. So if you ate 2 000 for sedentary but 4 000 for biking, double the veggie portions first, just to be on the safe side, and then add carbs and some protein for muscles.