~ Annie Bothma, Elite Athlete, IOPN Performance Sports Nutritionist (EQF Level 7. Masters), Running & Strength Coach
In my previous post, Fueling the Engine: How Much Do Athletes Really Need to Eat?, I detailed the negative consequences on performance and health as a result of Low Energy Availability (LEA) state or suffering from Relative Energy Deficiency in Sport (REDs). I outline the potential dangerous for athletes who are in a chronic energy deficit.
But, isn't that what is required for weight loss?
Many believe that eating less and training more is the ultimate formula for fat loss. However, when this pushes your body into Low Energy Availability (LEA) and triggers chronic stress, it sets off a cascade of damaging hormonal effects that can actually cause fat gain, not loss. Let’s break down why this happens—and why it’s more dangerous than you think and look at a more sustainable approach to weight-loss or body-composition goals.
The HPA Axis and Chronic Stress: Your Body’s Survival System
When your body is under constant stress—whether from under-eating, over-training, or life stress—it activates the Hypothalamic-Pituitary-Adrenal (HPA) axis. The HPA axis is your body’s central stress response system, designed to help you survive short-term threats. It triggers the release of cortisol, the stress hormone, which prepares your body to conserve energy, increase fat storage, and break down muscle for fuel in case the stress persists.
But here’s the issue: your body doesn’t distinguish between the stress of under-fueling and real life-threatening danger.
When you’re constantly dieting or training without proper recovery, your HPA axis stays in overdrive, pumping out cortisol. Chronically high cortisol levels lead to:
Increased fat storage (especially around the abdomen)
Muscle breakdown, which converts protein into glucose, robbing your muscles of strength and tone
Suppressed thyroid function, slowing your metabolism
Disruption in hunger hormones, making it harder to control your appetite and leading to overeating
This isn’t just about stress management—it’s about survival.
Your body believes it’s in a state of famine and activates every mechanism possible to store fat and preserve energy, despite your efforts to eat less or train more.
Hormonal Chaos: A Domino Effect
LEA and chronic stress don’t just disrupt cortisol—they throw off your entire endocrine system, which controls every aspect of your metabolism, hunger, and body composition. The hormones most severely impacted include:
Leptin (satiety hormone): As energy availability drops, so do leptin levels, which leads to increased hunger and cravings. Your body demands food, even though you’re trying to eat less.
Ghrelin (hunger hormone): As cortisol rises, ghrelin levels increase, making you feel ravenous despite being in a calorie deficit. This is your body’s way of screaming for fuel.
Thyroid Hormones: Chronic cortisol dampens the production of T3 and T4. These Thyroid hormone affects every cell and all the organs in your body by: Regulating the rate at which your body uses calories (energy). When these are suppressed, your metabolism slows down, making fat loss nearly impossible.
When these hormones are out of balance, your body becomes a fat-storage machine, prioritizing energy conservation and fat retention over fat burning. And here’s the kicker: even if you’re eating less and exercising more, your body responds by holding onto every calorie—storing it as fat to protect itself from perceived starvation.
Metabolic Adaptation: Slowing Down to Survive
When you are in a state of LEA, your body adapts by slowing down your metabolism—a process called metabolic adaptation. This isn’t just about burning fewer calories at rest. It means that your body becomes exceptionally efficient at holding onto fat while burning muscle for energy. Over time, this leads to:
Lower Basal Metabolic Rate (BMR): Your body burns fewer calories, even during sleep or rest.
Loss of Lean Muscle Mass: Muscle breakdown increases because your body sees muscle as expendable when energy is scarce.
Increased Fat Storage: Your body becomes more efficient at storing fat, especially in areas like the abdomen, even on fewer calories.
This is why extreme dieting doesn’t result in the long-term fat loss you expect. Instead, your body adjusts to protect itself, conserving fat and breaking down muscle—a scenario that leads to weight gain and a loss of lean body mass over time.
Creating More Fat Cells: The Long-Term Consequences
Here’s the truly jaw-dropping part: If you repeatedly push your body into cycles of LEA and stress, you can actually create more fat cells. Once fat cells are created, they don’t go away— they shrink or expand, but they stay with you for life. This means future fat loss becomes even harder because your body has more fat cells available to fill up.
This isn’t just about looking leaner—it’s about how your body is biologically programmed to resist fat loss when it’s under stress. Chronic LEA increases the risk of fat overshooting, where you regain more fat than you lost, making each dieting attempt more difficult than the last. That is why yo-yo dieting leads to more problems in the long term.
The bottom line is your body will start frighting against you.
Chronic LEA and stress don’t lead to sustainable weight loss. In fact, they trigger a series of hormonal and metabolic adaptations that make fat loss virtually impossible and fat gain inevitable. Your body is hardwired to protect itself from perceived threats—whether it’s from famine or an overzealous training and diet regimen.
To sum up, an excessive calorie deficit over an extended period will not only result in increased fat storage but also:
HPA axis dysfunction, where your body becomes resistant to stress management and recovery.
Thyroid suppression, leading to slower metabolism and energy loss.
Muscle loss, reducing your ability to burn fat and achieve the lean, athletic look you’re after.
Long-term fat gain, as your body creates more fat cells to protect itself.
A Sustainable Approach: Practical Application
But what if an athlete is genuinely overweight and needs to lose weight for metabolic health? The answer lies in timing. Just like you periodize your training for peak performance, you must also periodize body-composition goals within your training cycle.
Here’s how to sustainable work weight loss or body-composition into your training cycle:
Post-Event
Immediately after a race or event, consume a carbohydrate and protein shake or snack to replenish muscle glycogen and start the recovery process. Alongside adequate fluids and electrolytes to replenish your fluid losses. This curtails the stress response from exercise by shutting off cortisol production through the insulin response. Within 60-90 minutes, have a high-quality meal with protein, carbs, and healthy fats to promote recovery and micronutrient intake.
Post-Season
After the event, recovery is key. A person’s stress levels during training will determine how long recovery needs to be. The post-season focuses on bringing the body back to homeostasis by adjusting calories, improving micronutrient intake, and increasing dietary fats to restore hormonal balance.
Off-Season
This is where body-composition goals can be addressed. The off-season can be a time where an athlete strategically works with a sports nutritionist to optimize their body-composition before going into their next training cycle for their goal event. Training for peak performance and weight loss are conflicting goals and should be tackled at different times in an athlete’s training cycle.
Why Athletes Need to Avoid Severe Energy Restriction
Severely restricting energy intake may seem like a fast track to weight loss, but for athletes, it can do more harm than good. Combining extreme calorie restriction with intense endurance and strength-training programs increases metabolic adaptations that can actually slow down weight loss and cause significant health and performance issues.
Research shows that when energy restriction is too severe, lean, fit individuals can quickly lose lean muscle mass instead of fat, which compromises strength and performance.
For example, in one study, active military personnel on a 40% energy-restricted diet for 30 days lost 4.2% of their body weight, but 58% of that was lean tissue. In contrast, slower, more moderate energy restriction in sedentary individuals resulted in a greater percentage of fat loss. Additionally, athletes who adopt a slower weight loss approach (e.g., 0.7% of body weight per week) preserve more lean tissue and continue to improve strength gains compared to those who lose weight rapidly. (Manore, 2015)
Severe energy restriction during high-intensity training has a number of negative consequences, including:
Decreased performance: Loss of muscle strength, glycogen stores, coordination, and increased irritability.
Increased injury risk: Fatigue and loss of lean tissue make athletes more prone to injuries.
Nutritional deficiencies: Limited food intake can reduce essential nutrients, impairing health.
Risk of disordered eating behaviors: Extreme dieting can trigger unhealthy eating patterns.
Increased risk of dehydration: Especially in athletes following ketogenic diets.
Emotional distress: Hunger, fatigue, and stress from maintaining a restrictive diet.
The Solution: Work with Your Body, Not Against It
Set Realistic Expectations
Stop expecting rapid fat loss. Focus on building lean muscle and gradually improving body composition, rather than chasing quick fixes that damage your metabolism and hormones.
Sustainable Nutrition
Cycle between periods of maintenance and small, manageable deficits to prevent metabolic adaptation and keep your hormones balanced. Steer clear of severe deficits and ensure that you meet your daily energy requirements. A gradual calorie deficit is the best way to achieve sustainable weight-loss. Aim for a modest calorie deficit of around 300-500 calories per day. This will help you lose weight at a safe and sustainable rate.
Fuel Your Training
Ensure that your body receives an adequate amount of calories and nutrients to sustain your training and recovery. Timing of food intake around exercise training and spreading food intake throughout the day will assure the body has the energy and nutrients needed for exercise and the building and repair of lean tissue. Avoid fasted training and make sure you fuel properly after workouts. Additionally, remember to consume sufficient fluids and fuel during sessions lasting more than 60 minutes or involving high-intensity intervals.
Consume a higher protein intake when energy is restricted
When reducing energy intake, it is possible to reduce protein intake as well. For individuals who are active and maintaining their weight, it is recommended to consume between 1.4 and 1.8 grams of protein per kilogram per day. The exact protein amount needed during energy restriction is not yet determined and would vary based on the extent of energy restriction and the type of physical activity. Consuming around 25-35% of energy from protein is considered sufficient to prevent muscle loss, which typically corresponds to a diet with 2.0-2.4 grams of protein per kilogram per day. Nonetheless, some people may benefit from even higher protein intake if their aim is to maximize lean body mass growth.
Incorporate Strength Training for Better Results
Adding strength training to your routine is key to improving your metabolism and supporting weight loss. Strength training not only helps build muscle, but it also preserves lean body mass while you’re in a calorie deficit, making your weight loss more effective and sustainable. Focus on exercises that target major muscle groups, such as squats, lunges, deadlifts, and core exercises. Combined with proper nutrition and hydration, strength training will help you maintain muscle and optimize fat loss, improving overall body composition and performance.
It is always important to stay well-hydrated
It’s crucial to stay well-hydrated throughout the day and during training, whether you’re in a calorie deficit or not. Dehydration not only makes weight loss more challenging by slowing metabolism, but it also affects overall health and cognitive function. Chronic dehydration can impair concentration, reaction time, and athletic performance. Water should always be your primary choice for hydration, but for longer or more intense training sessions, electrolyte-rich drinks can be beneficial to replenish sodium, potassium, and other minerals lost through sweat. Proper hydration will help support recovery, maintain energy levels, and ensure optimal muscle function.
Manage Stress
Incorporate stress management techniques like mindfulness techniques like breathing and meditation, adequate sleep, and recovery activities. Keeping stress low may help prevent excess fat storage and hormonal disruption.
Monitor Biofeedback
Regularly check in on your energy levels, hunger, recovery, sleep, and mood. These signals are crucial indicators of whether your body is responding positively to your diet and training.
The things athletes SHOULD NOT be experiencing during a diet or calorie deficit include:
Loss of menstrual cycle
Extreme decrease in sex drive
Inability to focus
Complete loss of hunger or appetite.
Body temperature irregularities
Inability to sleep
Extreme mood swings
if you are experiencing any of the above symptoms while you are trying to lose weight or optimize body composition your approach is too aggressive and may cause more harm to your health in the long run.
Conclusion
Chronic LEA and too much stress aren’t just counterproductive—they’re harmful. By under-fueling and pushing yourself pass your physical limits, you’re not just stalling fat loss; you’re creating the conditions for fat gain, hormonal disruption, and long-term damage to your metabolism.
It’s time to shift your mindset and take a more sustainable approach that supports long-term health and performance if your goal is to lose weight or optimize body-composition.
When it comes to weight loss and body composition, many athletes struggle to find the right balance between nutrition, training, and recovery. Under-eating or overtraining can lead to low energy availability, hormonal imbalances, and even fat gain. Navigating these challenges alone can be overwhelming, which is why working with a professional is key. With expert guidance, you’ll get personalized strategies to optimize fat loss while maintaining muscle and health. Don’t rely on guesswork—reach out for tailored support to achieve sustainable body composition changes and reach your goals.
Contact me at anniesathletes@gmail.com to schedule a consultation and take the next step in optimizing your performance and health.
Resources
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Manore, M. M. (2015). Weight Management for Athletes and Active Individuals: A Brief Review. Sports Medicine, 45(Suppl 1), S83-S92. https://doi.org/10.1007/s40279-015-0401-0
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