How much should you eat before scuba diving? Expert nutrition tips

November 19, 2025 •

4 min read

According to the Divers Alert Network (DAN), proper hydration is key to mitigating the risk of decompression sickness (DCS), making your nutritional choices before a dive critical. This guide explains how much should you eat before scuba diving to maintain optimal energy levels and comfort underwater.

Quick Summary

This article outlines a nutritional strategy for scuba divers, focusing on the timing, quantity, and type of food to consume. It details optimal meals and snacks, highlights foods and drinks to avoid, and emphasizes the importance of hydration for safety and performance.

Key Points

Timing is Crucial: Eat a main meal 2-3 hours before diving to allow for proper digestion and prevent discomfort underwater.
Embrace Complex Carbs: Fuel your dive with a meal rich in complex carbohydrates like oats or brown rice for sustained energy release.
Avoid Heavy Foods: Stay away from fatty, greasy, spicy, and overly sugary foods that can cause nausea, indigestion, and energy crashes.
Prioritize Hydration: Drink plenty of water before, during surface intervals, and after dives to counteract dehydration and reduce the risk of DCS.
Snack Smartly Between Dives: Opt for light, easily digestible snacks like fruit, nuts, or energy bars during surface intervals to maintain energy.
Never Mix Alcohol and Diving: Alcohol is a diuretic that impairs judgment and increases dehydration and DCS risk, so it should be avoided entirely before diving.

Timing is Everything: When to Eat Before a Dive

Eating the right amount of the right food at the right time is crucial for a comfortable and safe scuba dive. Your body's digestion process requires blood flow, which can compete with the blood circulation needed for muscle function and temperature regulation during a dive. A heavy meal consumed too close to a dive can lead to discomfort, nausea, and sluggishness. Most experts recommend consuming a main meal approximately 2 to 3 hours before entering the water. This timeframe allows for proper digestion without leaving you feeling lethargic. For those diving multiple times in a day, smaller, light snacks can be eaten during surface intervals, ideally about 30 minutes before the next dive.

The Composition of Your Pre-Dive Meal

What you eat is just as important as when you eat it. The ideal pre-dive meal should be easily digestible and provide a slow, sustained release of energy to prevent a rapid blood sugar spike and crash.

Complex Carbohydrates: These are your primary fuel source and should form the bulk of your meal. Unlike simple sugars, complex carbs like oats, brown rice, or whole-grain pasta are digested slowly, providing steady energy throughout your dive.
Lean Protein: Including a moderate amount of lean protein, such as grilled chicken, fish, or eggs, helps support muscle function and endurance without overwhelming your digestive system.
Healthy Fats (in moderation): A small amount of healthy fats from sources like avocado or nuts can aid in satiety and provide long-lasting energy, but greasy or heavy foods should be avoided.

Foods and Drinks to Avoid Before Diving

Certain foods and drinks can negatively impact your dive experience by causing gastrointestinal issues or dehydration. Avoiding them is a key part of smart pre-dive preparation.

Fatty, Greasy, or Spicy Foods: These can slow down digestion and increase the risk of acid reflux or nausea, which can be very uncomfortable underwater.
Carbonated and Sugary Drinks: Carbonated beverages can cause bloating and gas to expand as you ascend, leading to stomach discomfort. High-sugar drinks and snacks can cause a blood sugar crash mid-dive, resulting in fatigue or light-headedness.
Alcohol: Acting as a diuretic, alcohol increases fluid loss and can lead to dehydration, which is a known risk factor for decompression sickness. Alcohol also impairs judgment and should never be consumed before diving.
Fermenting Foods: Foods like beans and cabbage can produce gas during digestion, which will expand with changes in pressure, causing uncomfortable bloating.

Comparison of Pre-Dive Meal Options

Here is a comparison table to help illustrate optimal versus poor pre-dive food choices.


Feature	Optimal Pre-Dive Meal	Poor Pre-Dive Meal
Composition	Balanced mix of complex carbs, lean protein, healthy fats	High in simple sugars, saturated fats, and processed ingredients
Timing	2–3 hours before a dive	Right before entering the water or during gearing up
Digestion Speed	Slow and steady energy release	Fast spike followed by a crash
Underwater Comfort	Reduces risk of nausea and bloating	Increases risk of gas, reflux, and discomfort
Energy Levels	Sustained and consistent	Fluctuating, can lead to fatigue mid-dive

The Crucial Role of Hydration

Proper hydration is a non-negotiable aspect of pre-dive preparation. Dehydration thickens the blood, making it harder for oxygen to circulate and increasing the risk of muscle cramps and DCS. Divers often don't realize they are losing fluids through breathing compressed air and immersion in water.

How to Hydrate Effectively

Start Early: Begin hydrating at least 24 hours before your dive by sipping water regularly.
During the Dive Day: Continue drinking water in small, consistent amounts throughout the day. This is particularly important between dives during your surface interval.
Post-Dive: Replenish lost fluids after your dive to aid recovery. Water, fruit juice without added sugar, or electrolyte drinks are excellent choices.

Planning for Multiple Dives

For multi-day or multi-dive trips, planning your nutrition is even more critical. A small snack during your surface interval can replenish your energy stores without causing digestive issues. Good options include bananas, energy bars rich in complex carbs, nuts, or a simple sandwich.

Adapting to Different Environments

Tropical Waters: In hot climates, you lose more electrolytes through sweat. Focus on fresh fruits and plenty of fluids to stay balanced.
Cold Waters: Your body burns more calories to stay warm in cold water. A slightly heartier, carbohydrate-focused meal might be beneficial to provide the necessary energy.

Conclusion: Your Dive Depends on Your Diet

Adopting a mindful nutritional strategy is an integral part of ensuring dive safety and maximizing your enjoyment underwater. By eating a balanced, easily digestible meal of complex carbs, lean protein, and healthy fats 2-3 hours before a dive, and staying well-hydrated throughout the day, you can avoid common digestive problems and energy crashes. Remembering what to avoid—heavy, fatty, sugary, and carbonated items—is equally important. Combining this dietary discipline with proper hydration will help you feel your best and perform safely during every scuba diving adventure. For more comprehensive information on dive safety, the Divers Alert Network is an excellent resource.

Frequently Asked Questions

Yes, eating a large, heavy meal right before scuba diving is not recommended. It can cause discomfort, bloating, and nausea, and may lead to a feeling of sluggishness underwater due to blood being diverted for digestion.

You should aim to eat a main meal 2 to 3 hours before diving. For light snacks during surface intervals, a 30-minute waiting period is typically sufficient.

The best foods are rich in complex carbohydrates for slow-release energy, like oats, whole-grain pasta, or brown rice. Combine these with lean proteins (grilled fish, eggs) and healthy fats (nuts, avocado) in moderation.

Caffeine has a diuretic effect, which can increase fluid loss and contribute to dehydration. While some seasoned divers may tolerate a small amount, it is best to avoid it, especially for newer divers, as dehydration is a risk factor for decompression sickness.

For surface intervals, light and easily digestible snacks are best. Good options include bananas, fruit, energy bars with complex carbs, nuts, or crackers to replenish energy without causing stomach issues.

Proper hydration is critical because it helps maintain optimal blood circulation. Dehydration thickens the blood, which can lead to muscle cramps, fatigue, and is a significant risk factor for decompression sickness.

Yes, certain foods like beans, cabbage, and other fermenting items can produce gas during digestion. This gas can expand at depth and with ascent, causing uncomfortable bloating and gastric issues.