Organ Systems and Performance – Episode 10: The Stomach

INTRODUCTION

The stomach is where digestion begins in earnest. It’s not just a holding tank, it’s a chemical reactor, a muscular churner, and a gatekeeper for nutrient absorption. From protein breakdown to satiety signaling, the stomach sets the stage for everything that follows in the digestive tract.

For aging lifters and performance-focused clients, stomach health is essential for recovery, appetite regulation, and nutrient utilization.

STRUCTURE AND FUNCTION

The stomach is a muscular organ divided into regions: the fundus, body, and pylorus. It performs three key functions:

• Mechanical digestion: churning food into chyme  
• Chemical digestion: secreting hydrochloric acid (HCl) and enzymes like pepsin  
• Regulatory signaling: releasing hormones like ghrelin and gastrin

These processes prepare food for absorption in the small intestine and influence hunger, fullness, and metabolic response.

PROTEIN DIGESTION AND MUSCLE RECOVERY

The stomach initiates protein digestion through pepsin, which breaks down long chains into smaller peptides. This process is acid-dependent, without sufficient HCl, protein digestion stalls.

For lifters, this matters. Poor stomach acid means poor amino acid availability, which compromises muscle repair, growth, and immune function. Aging adults often experience reduced acid production, making protein timing and digestion even more critical.

SATIETY SIGNALING AND APPETITE CONTROL

The stomach communicates with the brain via hormones and stretch receptors. Ghrelin signals hunger, while gastric distension contributes to fullness. If stomach function is impaired through inflammation, overeating, or poor meal timing, these signals become distorted.

This leads to erratic hunger, poor portion control, and disrupted energy balance. For clients managing body composition, restoring stomach rhythm is key to sustainable eating habits.

ACID BALANCE AND MICROBIAL DEFENSE

Stomach acid isn’t just for digestion, it’s a frontline defense against pathogens. Low acid allows bacteria to survive and reach the intestines, increasing the risk of infection and dysbiosis.

Antacids and acid blockers, while sometimes necessary, can impair this defense. Long-term use may lead to nutrient deficiencies (especially B12, iron, and magnesium) and microbial imbalance. Coaches should be aware of these risks when working with clients on medications.

DIETARY STRATEGIES FOR STOMACH HEALTH

Supporting the stomach starts with mindful eating and strategic food choices:

• Eat slowly and chew thoroughly to support mechanical breakdown  
• Include protein in every meal to stimulate acid and enzyme production  
• Avoid excessive liquid intake during meals, which can dilute acid  
• Limit processed foods and irritants like alcohol, NSAIDs, and excessive caffeine  
• Consider digestive bitters or apple cider vinegar before meals (if tolerated) to support acid production

Meal timing also matters. Large, late-night meals can disrupt gastric emptying and sleep quality.

COMMON LIMITERS AND COACHING INSIGHTS

Clients often ignore stomach health until symptoms appear, bloating, reflux, or nausea. But subtle signs like poor recovery, inconsistent appetite, or nutrient deficiencies can also point to gastric dysfunction.

For aging lifters, stomach efficiency declines. Coaches can help by emphasizing protein quality, meal structure, and acid-supportive habits. Education around digestion should be part of every long-term health strategy.

CONCLUSION

The stomach is more than a pit, it’s a precision tool for digestion, signaling, and defense. Supporting its function improves nutrient absorption, appetite regulation, and recovery.

Feed it wisely. Respect its rhythm. Protect the organ that starts the transformation from food to fuel.