Learn how you’re putting yourself at risk for serious health consequences if you’re not eating enough calories for the amount of classes you're teaching. Guest Author: Timothy James Butler RD, LD
How you’re putting yourself at risk for serious health consequences if you’re falling short.

Guest Author: Timothy James Butler RD, LDSimply put, a calorie is a unit of measure for the energy we get from food and beverages. The amount of calories a person needs depends on many factors, including their age, gender, lean muscle mass, and activity levels. Unfortunately, calorie management can be much more complicated. To maintain optimal health and performance we must balance the number of calories we consume with the number of calories our bodies burn. And for those that expend a great number of calories from exercise like military personnel, recreational and professional athletes, the task can be troublesome (1 -5).

Group exercise instructors, especially those teaching multiple classes regularly, can fit into this same category. A smaller (50 kg) fit-pro could need anywhere from 250 – 600 calories for each one hour class*(using METs). Now, multiply that by 3 classes and you’ve just used an additional 750 – 1800 calories in one day! If you’re a larger (100kg) fit-pro, just double it; you would be needing 1500 – 3600 calories depending on the intensity of class being taught. This could bring your total daily needs up to 2500 – 5100 calories! To put that in perspective – a large cheese pizza is roughly 2000 calories.

Previous observations of military and athletic populations show a consistent caloric deficit (1 -5). More recently, scientists have been able to define the consequences of a chronically calorie deficient diet and the International Olympic Committee (IOC) released a consensus statement on Relative Energy Deficiency in Sport (RED-S) in 2014.

The syndrome of RED-S refers to impaired physiological function including, but not limited to, metabolic rate, menstrual function, bone health, immunity, protein synthesis, cardiovascular health caused by relative energy deficiency. The cause of this syndrome is energy deficiency relative to the balance between dietary energy intake and energy expenditure required for health and activities of daily living, growth and sporting activities.

Fatigue, increased incidence of injury, trouble losing body fat, increased illness or infection, and trouble building muscle are possible initial symptoms that indicate a need for a RED-S assessment. If any of these symptoms ring home, the first thing to consider is decreasing activity levels. You may have to drop some classes or switch with a colleague for less intense ones. Also consider increasing caloric intake. Think about increasing portion sizes at meals, or increasing meal frequency, or adopting higher calorie food choices like nut butters, fuller-fat dairy foods, and dried fruit or fruit juices.

If you or any of the athletes you work with may be at risk for RED-s, please contact your local Registered Dietitian (RD). RD’s can accurately assess normal daily caloric intake versus how much you, as an individual, may need. They can also provide great tips on how to correct or improve any dietary concerns you may have. You can search online for local experts here, and even a tool to find nutrition professionals with a specific expertise like Sports Nutrition.


(1) Richmond VL, Horner FE, Wilkinson DM, Rayson MP, Wright A, Izard R. Energy balance and physical demands during an 8-week arduous military training course. Mil Med. 2014 Apr;179(4):421-7. doi: 10.7205/MILMED-D-13-00313.
(2) Slater J, McLay-Cooke R, Brown R, Black K. Female Recreational Exercisers at Risk for Low Energy Availability. Int J Sport Nutr Exerc Metab. 2016 Oct;26(5):421-427. Epub 2016 Aug 24.
(3) Slater J, Brown R, McLay-Cooke R, Black K. Low Energy Availability in Exercising Women: Historical Perspectives and Future Directions. Sports Med. 2017 Feb;47(2):207-220. doi: 10.1007/s40279-016-0583-0.
(4)Mountjoy M, Sundgot-Borgen J, Burke L, et al. The IOC consensus statement: beyond the Female Athlete Triad—Relative Energy Deficiency in Sport (RED-S). Br J Sports Med 2014;48:491-497.
(5) Bartlett, Carrissa G.; Stankorb, Susan. Physical Performance and Attrition Among U.S. Air Force Trainees Participating in the Basic Military Training Fueling Initiative. Military Medicine . Jan2017, Vol. 182 Issue 1, pe1603-e1609. 7p.

Fit Pros: Are you Eating Enough Calories? 1

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