Pre-Race Weight Loss: Helpful or Harmful?

by Nancy Clark, MS, RD, CSSD

Many runners fantasize about losing weight (“Wouldn’t it be nice to lose a few pounds…”). Unlike some athletes who have to lose weight in order to meet a specific division for their sport (such as boxers or wrestlers), runners often choose to target a lower-than-normal weight for a specific race. (Note: Dropping weight once or twice a year is far healthier than trying to keep a low weight all year round!)

Runners, like skaters, dancers, and gymnasts, who try to maintain a long-term low weight generally end up living in “food jail.” While this article will not focus on the problems with long-term under-eating, it’s well known that keeping the body at an unnaturally low weight sets the stage for injury after injury.  This article will offer help for runners who want to lose weight for a short-term goal, such as a specific race.

Runners who seek to lose pre-race weight may believe being lighter will offer the advantage of having less weight to lug around and enhance their ability to run faster. Yes, there’s a lot of talk about “power to weight ratio.” Unfortunately, the body is not a robot and does not work quite as mathematically as many people would like it to. As one champion commented, “I ran the same times in the same race despite being 8 pounds heavier a year later.”

A big problem with dropping pre-race weight is too many runners target a minimal weight that might not be their best performance weight. I suggest you focus less on a number on a scale and instead tune into where you compete well.  And whatever you do, don’t resort to last-minute restrictive dieting to reach an unrealistic weight goal. Inadequate pre-event fueling can contribute to early bonking, poor performance, and disappointments. If you eat well and compete at your natural weight, you will be better able to run past any skinnier but depleted opponents.

So what are weight-focused runners supposed to do? Obviously, they are not supposed to wait until the last few days before an event to shed pounds by abstaining from food and water, over-exercising, and abusing their bodies. The better path is to start chipping away at weight loss weeks in advance. If you have to lose 10 pounds, give yourself at least 5 to 10 weeks to do so, if not more.

Ideally, runners should first have their body fat accurately measured to determine if they even have fat to lose. Females should not drop below 12% body fat, males no less than 5%. Some runners might need to lose muscle to be able to reach their weight goal—and that seems counter to being a strong and powerful athlete.

What's the best way to lose weight?

The best way to lose weight is to push yourself away from the dinner table before you eat your fill! Plain and simple, you have to eat less than your body requires. Easier said than done. Hence, these tips might be helpful.

  • Knock off only 300-500 calories/day from your typical daily intake. Do NOT chop your food intake in half or eat as little as possible! As an athlete, you need fuel to train.
  • Fuel by day; diet by night. Plan to lose weight when you are sleeping—not when you are trying to train hard.
  • Surround your workout with food, so that you fuel-up and refuel.
  • Do NOT cut out all carbohydrates. Runners need grains, veggies, and fruits to optimize their muscle glycogen stores. A very low-carb diet results in depleted glycogen, “dead legs,” and inability to train hard.
  • Enjoy carb-protein combinations: carbs to fuel muscles; protein to build and repair muscles. Protein is also satiating and can help curb hunger.
  • When it gets to “crunch time,” target about 1.5 g carb, 1 g protein, and 0.5 g fat per pound of body weight (3 g carb, 2 g pro, 1 g fat/kg). This means a 150-lb (68 kg) runner would target about 200 g carb, 135 g pro, and 70 g fat (~1,950-2,000 calories/day) during the weight-loss weeks.
  • Divide the calories into 4 food buckets and eat a meal at least every 4 hours. (The clock starts ticking when you get up in the morning). A runner who trains from 6:30 to 7:30 a.m. could divide breakfast into 100-200 calories pre-workout at 6:00ish, then 400 calories post-workout at 8:00; eat early lunch (500 cal.) at 11:00ish; later lunch (400-500 cal.) at 3:00ish, and dinner at 6:00-7:00ish (500 cal.). The rest of the night, chew gum, drink herbal tea, go to bed early? (If you are ravenous, please eat a bit more...)
  • If you don’t have fat to lose, you can shed a few pounds by restricting fiber to reduce gut contents. If you have long hair, you could also contemplate chopping it off and donating it to Locks for Love (ha!)..

After the race…

The standard advice for weight-focused runners is to just lose the weight and keep it off. This makes sense intellectually, but it is the opposite of what the body wants to do physiologically. After having been underfed, hungry runners experience a very strong drive to eat, if not over-eat, and regain all the lost weight. This happens with most dieters, athletic or not.

The urge to devour food after having lost weight is physiological, and not simply due to lack of will-power. Here’s the analogy: If you hold your breath for too long, you will uncontrollably gasp for air. If you rigorously restrict calories for too long, you will uncontrollably grab for food and easily binge-eat. No wonder eating disorders blossom in weight-focused sports!

The bottom line

Any way you look at it, losing weight when you really are not over-fat in the first place is not much fun. Yes, it creates a bond with others doing the same thing—misery loves company—and is embedded into the culture of weight-focused sports like running. Ideally, it’s time to change that culture to focus more on health (both short and long term) and injury reduction. Working with a sports dietitian can help with you fuel well to perform well. To find your local RD CSSD (Registered Dietitian who is a board Certified Specialist in Sports Dietetics), please use the referral networks at www.EatRight.org and www.HealthProfs.com

References:

Langan-Evans C. at al. 2021. Nutritional considerations for female athletes in weight category sports. European Journal of Sports Science

Burke, L, et al. 2021. ACSM Consensus Statement on Weight Loss in Weight-Category Sports. Current Sports Medicine Reports


NancyClarkLogo.jpegSports Nutritionist Nancy Clark, MS, RD counsels both casual and competitive athletes in Newton MA (617-795-1875). Her best-selling Sports Nutrition Guidebook is a popular resource, as is her online workshop and books. For more information visit www.NancyClarkRD.com.


Loading Conversation

Partner Clubs

Partner clubs offer group runs and local races to the Capital Region running community

Create Account



Log In Your Account