Can you relate?
You finish a long or hard workout and you have no appetite. You'd think you'd be ravenous after a tough training session but eating is the last thing on your mind. Even worse, the thought of food leaves you feeling nauseous. But come the evening or the next morning, you are starving and you can't seem to stop the nagging hunger pangs and fill the bottomless pit in your stomach.
If you said "that's me!" you are not alone. Having a decreased appetite after certain training sessions is very common. However, just because this is a normal phenomenon, this doesn't mean that its ok not to eat. The food you eat post workout provides the fuel to power future workouts and gives your muscles the nutrients needed to properly recover from the previous session.
Here are a few reasons why your appetite is blunted post workout:
- Internal body heat - Contracting muscles produce heat. Around 20% of the energy produced by contracting muscles is used for muscle contraction and the rest is convereted into heat energy, which results in an increase in body temperature.
- Blood flow - A normal effect of exercise is the diversion of blood away from the gut so that more oxygen can go to the working muscles. Less blood flow to the gut means less hunger sensastions.
- Dehydration - Staying hydrated is critical for optimal body functinoing. Dehydration can make you feel tired, nauseated, fatigued and sleepy.
- Nutrient deficiency - A decreased/poor appetite is common in several nutrient deficiencies such as iron, magnesium, B vitamins, folate and zinc.
- Hunger hormones - Ghrelin is a peptide hormone predominantly produced by the stomach. It plays a key role in stimulating appetite and energy intake. Intense or prolonged exercise supresses ghrelin.
- Dieting and/or body image concerns - You are disconnected from your body's cues. You've conditioned yourself to ignore your hunger cues and undereat to meet your body composition goals.
For athletes focused on performance, health and sport longevity, consuming nutrition and fluids post-exercise is critical. Insufficient energy intake may impair tissue repair, induce excessive fatigue and reduce the ability to stay consistent with training. While counterintuitive, you need to take in calories even when you aren't hungry.
This is called Mechanical Eating and it's the opposite of Intuitive Eating.
Intuitive eating means eating only when you are actually hungry and honoring your body's hunger and fullness cues to make food decisions. While this may work for the normal population, avoiding food after intense/long training due to not being hungry will compromise training adaptations and your ability to perform well in your next workout.
Mechanical eating means having a specific plan as to what and when you will eat when you don't experience hunger cues.
Because proper recovery can help with performance gains, building lean tissue (strength gains), optimizing health and reducing the risk for injury, it's important to have a plan for post workout nutrition when you lack an appetite to eat post workout. Consider liquid calories as a start and aim to eat smaller carb/protein portions every hour in the 4 hours post workout to help with recovery. If you continue to struggle with your intake post workout, reach out to a sport RD to help create a personalized plan for your needs.