Going through short voluntary periods of time without eating is part of many cultural and religious practices throughout the world and pose no real health risks to otherwise healthy people. Intermittent fasting (IMF) is another experience altogether because the goals are usually weight loss or for perceived health value, and fasting can become like a lifestyle.
Proponents claim that IMF is the key to quick weight loss and improved metabolic biomarkers and blood tests such as cholesterol, triglycerides and reduced C-reactive protein which is a marker of inflammation. There are no shortage of internet pages touting “impressive health benefits” and “research backed results”, but many of these studies are short-term and on populations nothing like dancers. Let’s take a closer look at the research and consider whether fasting is good for dancers.
Actual caloric needs of real life dancers
These estimates are based on my experience as a former professional dancer and now as a dietitian who has been working with hundreds of dancers over the past 10 years doing personalized dietary plans and nutrient calculations. Energy or caloric needs vary by age, size, gender and intensity of schedule, but these are averages to maintain a dancer’s current weight and energy levels. Dancers who are in a growth spurt or who are working toward gaining muscle would need to eat more than these amounts below.
Female pre-professional dancers ages 13-18: 1650-2200 calories and 55-75 grams of protein per day.
Female professional dancers ages 18 and up: 1750-2300 calories and 60-70 grams of protein per day.
Male dancers ages 16 and up: 2200-3500 calories and 70-105 grams of protein per day.
Food is broken down into glucose for immediate energy needs, or it’s stored in the form of glycogen for later energy needs. When extra energy intake (aka calories) is consumed (over and above the body’s immediate needs and glycogen storage capacity), it can be stored as fat. I’ve written extensively about how calorie deficits affect athletic and mental performance, but the bottom line is that the body runs on fuel. In absence of fuel from food, the body has to make strategic adaptations that include breaking down and “burning” of muscle tissue and ultimately lowering energy needs. When no calories (or far too few calories) are taken in through food, there are well documented dips in energy, jump height, mental performance, mood and balance. Many dancers who have gone though times of restrictive eating will report that that’s when their injuries happened.
I spent a year researching and documenting pre-professional dancers and energy intake through their day. What I found was that dancers with the highest energy deficits and the longest energy deficits in the 24-hour time period had significantly higher risk for injuries. Even for dancers who just skipped one meal we still found higher rates of injuries.
Types of IMF
In the 5:2 method, dieters eat regularly for five days of the week and choose two non-consecutive days to eat very restricted calories. Fasting days would be only 500 calories for women and 600 calories for men. Modified fasting is a similar approach in which dieters restrict up to 75 percent of caloric needs on fasting days. Meaning they only eat 20-25 percent of their nutrient needs on any given day. Alternate Day fasting is eating normally for a day and then fasting the next consecutive day on and off. In practice, many who state they are intermittent fasting are actually just skipping meals, particularly breakfast. Sometimes this is called spontaneous fasting.
Results vary considerably between studies, and many of the studies on IMF that show weight loss have been done on small groups of participants who are in the overweight or obese category. We can’t draw the same conclusions for dancers who are physically much more active than these small study populations and who are not overweight to begin with. Many studies on fasting or restrictive dieting found that participants gained back the lost weight plus extra over the long term. I have found this to be true in the 10 years I’ve been working with dancers. Often, dancers will see weight gain, specifically fat mass gain, after a period of overly restrictive eating, unless they are working with a dietitian who understands how to help transition them to normalized eating. Certainly, it’s very possible to get back to normal eating without the boomerang weight gain that sometimes happens.
Several studies on athletic populations found that significant energy deficits in the day were actually correlated to higher body fat percentage in the long term. This is because of the adaptive response the body does to starvation and the natural human tendency to overeat when finally given the chance to have a normal meal after fasting. In addition, if the body is losing muscle tissue because it’s being burned as fuel while in a starvation state, and then the dancer overeats dinner or overeats on a non-fasting day, then there is an excess of calories that get stored as fat. Resulting in lower muscle mass and higher body fat percentage and increased injury risk.
The HELENA study found that long-term weight loss was better in study participants that followed a healthy eating plan over time that included all food groups, compared to participants who engaged in IMF who had a harder time keeping weight normalized in the long run.
According to the HELENA study, participants who regularly skipped breakfast had lower intakes of vitamin D, C, E, B12 and Folate. These vitamins affect immune function and energy metabolism. Breakfast is such an important meal for dancers if they want energy and ease in keeping weight stable over time.
Increases risk for eating disorders
IMF is also called intermittent calorie restriction, which should be a red flag for anyone with a history of disordered eating or who is at a higher than average risk for eating challenges. It’s well documented that trying restrictive dieting can potentially lead down a road toward disordered eating in those at risk. Restrictive eating patterns might be hard to stop, or it could be hard to transition to a more normalized healthy eating pattern. If dancers find this is true for them, then reaching out to a dietitian is a key step in getting back to a healthy way of eating that is right for the unique needs of dancers. Dancers should never have fear that if they stop engaging in IMF or any kind of restrictive eating, that they will just gain weight. A well designed, healthy eating plan will get a dancer back on track in little time without rollercoaster weight gains or losses.
By Emily C. Harrison MS, RD, LD of Nutrition for Great Performances.
Emily Cook Harrison MS, RD, LD
Emily is a registered dietitian and holds both a bachelor’s and master’s degree in nutrition from Georgia State University, USA. Her master’s thesis research was on elite level ballet dancers and nutrition and she has experience providing nutrition services for weight management, sports nutrition, disordered eating, disease prevention, and food allergies. Emily was a professional dancer for eleven years with the Atlanta Ballet and several other companies. She is a dance educator and the mother of two young children. She now runs the Centre for Dance Nutrition and Healthy Lifestyles. She can be reached at email@example.com