January 2023

Gastric Sleeve Surgery: Tips for Staying Hydrated

Water plays a critical role in health for everyone, whether you've had Gastric Sleeve or Bypass Surgery or not. Our bodies are made up of over 65% water, so it's genuinely essential to life. It's often said that if stranded, we could survive many weeks without food, but no more than about three days without adequate water.

After Bariatric Surgery, staying properly hydrated becomes even more important. Let's explore why, and how to make it easier.

Why Hydration Matters So Much After Surgery

Dehydration is one of the most common issues after Bariatric Surgery, in fact, it's a leading reason for hospital readmission among Weight Loss Surgery patients. The good news is that it's very manageable with the right approach: small sips, taken often, keep you hydrated and help prevent fluid loss.

This is why you'll hear so many WLS patients repeating the mantra: "sip, sip, sip."

The goal is to work up to around 8–10 glasses (about 2 litres) of fluid each day, but because your stomach capacity is now much smaller, this has to be done gradually across the day rather than in large amounts at once.

How Much Water Do You Actually Need?

The standard recommendation for adults is around 8 cups (250ml each) per day, just to maintain hydration. Some people will need more depending on their body size, activity levels, and what else they're eating and drinking.

A couple of things worth knowing:

  • Coffee has a mild dehydrating effect - for each cup, it's often said you lose around one and a half cups of water.
  • Alcohol is another culprit - many hangover symptoms come down to its dehydrating effect on the body.

Signs You Might Be Dehydrated

Keep an eye out for:

  • Lethargy or feeling drained
  • Headaches
  • Muscle cramping
  • Dry mouth
  • Cracked or sore lips

Watch Out for "False Hunger"

Left unchecked, dehydration can actually trigger false hunger signals. It's a survival mechanism, your body's way of nudging you to eat, in the hope that food will provide some of the water it's missing.

So if you're feeling hungry between meals, it's worth having a drink first and seeing whether the feeling settles.

Don't Forget Electrolytes

If you're drinking plenty of water for your body size and activity levels but still feeling flat, the issue might be electrolytes, the minerals that help water actually get absorbed into your cells. When these are low or out of balance, hydration can suffer even when you're drinking enough. An electrolyte supplement can help here, your healthcare team can advise if it's appropriate for you.

Why Water Is So Important

Water is fundamental to how your body functions. It:

  • Regulates body temperature
  • Keeps your joints lubricated
  • Supports your immune function and natural defences
  • Delivers nutrients to your cells
  • Supports healthy kidney function
  • Helps keep your organs working properly

Staying hydrated really is one of the simplest and most important things you can do for your health after surgery. Keep a water bottle with you, sip consistently throughout the day (away from meals), and your body will thank you for it.

Always follow the hydration guidance of your surgical and healthcare team. If you're concerned about dehydration, seek advice promptly.

Jacqui Lewis
BHSc Nutritional and Dietetic Medicine