As a sports dietitian, I have seen many runners and triathletes with an intense fear of weight gain. They know they’re under fueled, but being afraid holds them back from eating more. I am here to let you know that this isn’t always the case! Can you eat more without gaining weight? Absolutely.

In today’s article, I will be going over all of the deets on how this can happen as an endurance athlete.

Keep reading to learn more about your body’s response to under fueling, metabolic adaptation, and eating more (in the right way) could potentially help you!

By the way… if you’re an endurance athlete reading this- you also need to check out my carb loading guide!

Are you afraid if you eat more you’ll gain weight? You don’t need to be.

I started working with a male ultra-distance trail runner in his late 40’s in early 2021. This awesome dude does year-round high-volume training. You’d think that he’d have no trouble keeping weight off. But alas, over the past two years he’d been experiencing gradual weight gain. About 20 pounds total. He reported that he’d been watching his eating, but his weight continued to trend up.

I calculated his nutrition needs and with his training load, his body needed about 3,000 calories/day.

And he was averaging about 1,800 calories/day.

How do you gain weight at a 1,200 calorie deficit? Well, the answer has to do with metabolic adaptation.

Metabolic Response

Yes. Our bodies are highly adaptable, including our metabolism. When the body enters into a calorie deficit, our body is really smart about finding ways to survive and will shift to keep things running, including:

• Decreasing the metabolic rate. Essentially, reducing the amount of energy it needs to function.
• Exercise is going to become more difficult, and as a result, you’re not burning as many calories.
• Daily movements will decrease (aka: you’ll have less energy).
• Your digestion will slow, allowing more energy to be used.

In the case of my trail runner, I worked with him to reach 2,800-3,000 calories/day. To eat that many calories day-in and day-out is a lot of work. It takes dedication from morning until evening to fuel your body well. And the results have been spectacular. Within the first month, he lost about 5 pounds. By the 2nd month, he’d lost 10.

The best part? He was running faster and stronger than he has in years. Partly because of the leaner body composition, but also because he’s changed his mindset and composition of his nutrition. He’s fueling for his training, not training so that he can eat more. He’s eating balanced meals and snacks from breakfast until bedtime. Adequate protein. Consistent hydration.

How is it possible for him to eat 1,000 calories more each day and lose weight? Let’s talk about it.

Improving Metabolic Output

Improving an athlete’s metabolic output involves gradually increasing calories over time to allow you to eat more food without gaining weight.

Shifting from under-fueling to aligning your calorie intake with calorie output, the body can adapt back to a higher metabolic output.

What we see from athletes when we increase and improve their fueling:

• Metabolism increases.
• Your workout capabilities increase as there’s more energy available, and therefore, can burn more energy.
• More energy to accomplish more daily movement, and therefore, burn more energy.
• Digestion will return back to normal and less energy will be used.

So to answer the question, can you eat more without gaining weight?

Yes, it’s possible. But, to achieve you need to work through this process gradually to restore that metabolic output.

It’s not a perfect process. Here are a couple of other key factors that can help with performance nutrition success:

1. As we age, our metabolism does gradually decline due to gradual muscle loss. So it’s important to also make sure you’re including strength workouts in your training regimen. Maintaining that lean muscle will help keep that metabolism nice and high.
2. You need to have a good sense of what calorie range you need to eat without gaining weight. And you need to be fairly consistent.
3. Tend to get better results with increased activity as more calories can be sent to muscle growth instead of maintaining fat stores. Plus, it gives you more flexibility with calories.
   

Looking to learn more about my eating philosophy as a sports dietitian? Check out my post on what a flexible eating style for athletes is!

The Takeaway

Are you afraid to gain weight? I get it. But, there’s a balance between fueling adequately to perform well as an athlete and not seeing weight gain.

Do you have follow-up questions? Send me an email at alex@alexlarsonnutrition.com and ask! Seriously, I’d love to hear from you.

If you’re an endurance athlete looking to get started in having more energy and better performance while eating more, you’re in the right place. I’m so proud to be part of the journey of endurance athletes who are able to reach new levels of performance and no longer restrict their eating through my nutrition coaching program.

Fill out the application and let’s talk more about where we can take your nutrition. There is no better time to invest in yourself and your goals as a runner or triathlete!