When Is the Best Time for Athletes to Lose Body Fat Without Hurting Performance?

Increasing speed requires the consistent and careful application of training stress. However, gaining body fat works directly against this goal. One of the most difficult challenges endurance athletes face is creating a caloric deficit large enough to lose body fat while maintaining training volume and quality.

A caloric deficit can accelerate fatigue, reduce energy availability, and negatively affect workouts. As the saying goes, you can’t train hard on a salad. This raises an important question for runners, cyclists, and endurance athletes:

When is the best time to reduce body fat—and what is the smartest way to do it without sacrificing performance?

Why Body Fat Loss Improves Speed and Endurance Performance

One of the most important determinants of speed and endurance performance is your power-to-weight ratio. In many cases, it is the limiting factor.

• Runners typically improve by ~2.5 seconds per mile for every pound of body fat lost. Losing 10 pounds can translate into an 11-minute improvement in a marathon.

• Cyclists rely heavily on watts per kilogram, often called the sport’s “golden ratio.”

• VO₂ max is expressed in milliliters of oxygen per kilogram of body weight, meaning lighter athletes with the same aerobic capacity perform better.

If you’ve ever been tested, ask the administrator to plug in your goal weight instead of your current weight—the difference can be eye-opening.

Just like increasing the speed of a race car, you can either:

• Add horsepower (fitness), or

• Reduce weight (body fat)

Focusing on only one side of this equation means leaving performance gains on the table.

A Simple Test to Feel the Impact of Excess Body Weight

Cyclists can perform a simple test: ride with a fluid pack weighing about 10 pounds. Heart rate and perceived exertion rise quickly, especially on climbs.

Runners can try walking (not running) uphill with added weight. The impact becomes obvious very quickly.

Once you feel how extra body fat affects performance, the next step is determining when to remove it.

The Best Time of Year for Athletes to Lose Body Fat

For most endurance athletes, the best time to reduce body fat is during the base season or off-season, typically in the fall and winter.

Why the Off-Season Is Ideal for Fat Loss

• Training is often more informal, with fitness maintenance rather than progression as the goal.

• Racing volume is low, and events are usually “C” or training races.

• Training intensity is lower, emphasizing the aerobic energy system.

• Glycogen depletion is less critical than during race-specific training.

• Long, slow distance training relies more heavily on fat as a fuel source, reinforcing metabolic efficiency.

During this phase, a caloric deficit has minimal impact on performance, making it the most strategic time to lean out.

Why Winter Fat Loss Is So Challenging for Athletes

Despite being the ideal time physiologically, winter is often the hardest time to lose body fat:

• Shorter days reduce training opportunities.

• Cold weather forces more indoor training, often reducing volume.

• The holiday season encourages overeating.

• Some athletes take extended breaks, lowering metabolic rate.

• Cold exposure can increase appetite.

The athlete who emerges from winter lighter and leaner starts the season with a significant competitive advantage.

How to Lose Body Fat Without Losing Energy or Muscle

Step 1: Identify Your Caloric “Sweet Spot”

Fat loss requires a caloric deficit, but over-restriction is counterproductive. Cutting calories too far below resting metabolic rate can:

• Slow metabolism

• Reduce training quality

• Increase muscle loss

Determine your target intake by:

• Measuring resting metabolic rate (best option), or

• Using a validated formula that accounts for height, weight, age, and activity level

The goal is a moderate deficit that preserves energy, muscle, and training consistency.

Step 2: Track and Adjust Intake Strategically

Working with a Registered Dietitian can be extremely valuable, but many athletes succeed using online food tracking tools.

Athletes tend to eat the same foods repeatedly. Simply understanding the caloric content of your regular meals gives you control without obsessiveness.

Practical Nutrition Strategies for Off-Season Fat Loss

• Remember: It’s a holiday, not a “holimonth.”

• Eat 5–7 smaller meals per day to maintain metabolic rate.

• Include carbohydrates, protein, and fat at each meal to stabilize blood sugar.

• Know the approximate calorie content of your meals.

• Watch fat intake—it is calorie-dense and easily stored.

• Prioritize protein, which has a higher thermic effect and preserves muscle.

• Eliminate sports drinks and bars on low-volume days.

• Match caloric intake to daily training load.

• Eat before parties or holiday meals.

• Reduce portion sizes and choose lower-fat alternatives.

• Limit alcohol intake.

• Avoid high-density carbohydrates (pasta, bread) when training volume is low.

Slow and Steady Fat Loss Wins

Sustainable fat loss is gradual. Rapid weight loss often comes from water and lean tissue—both of which harm performance.

By deferring short-term gratification during the winter, you set yourself up for stronger climbing, faster racing, and better results when the season begins.

Lean now. Fly later.