Harvard Medical School's website provides calorie expenditure estimates for weight training. A 30-minute weight-training session burns about 90 calories if you weigh 125 pounds. If you weigh 155 pounds, the same weight-training session will result in 112 calories burned. Aerobic exercises burn calories at a notably quicker rate than weight lifting.
Note that this is a ratio, not the formulae you are looking for. So, a 15:5:15 ratio would be ideal (note the ratio of 3:1:3). The company Scotts has just released what appears to be an ideal palm fertilizer with microelements, magnesium and calcium. Consider buying a slow release fertilizer. It is more expensive but probably better for the plants and less labor intensive.
Once they are properly located, caring for foxtail palms is relatively simple. Once you grow these specimens you will quickly learn how to take care of the foxtail palm. Through experience and experimentation you will determine which foxtail palm fertilizer is best for your conditions and which varieties of foxtail palm trees you prefer to grow.