Diet, hydration and exercise habits to support your weight loss injection

Weight loss injections work best alongside good habits around food, water and movement. Aiming for at least 2-3 litres of water a day, eating smaller more frequent meals, rather than three large meals, and adding regular gentle exercise can reduce side effects and make the medication more effective.

Who this applies to

This article applies to patients currently taking a weight loss injection (such as Mounjaro or Wegovy) prescribed by us. The advice here is general lifestyle support, not a replacement for any clinical guidance specific to your case.

Water

Many patients do not know that the recommended water intake while on weight loss injections is at least 2-3 litres a day. Low water intake can cause side effects such as nausea, headaches and constipation, and can also slow your progress. If 2-3 litres feels like a lot, spread it out across the day rather than trying to drink it all at once. Please note drinking or eating a lot too close to bedtime can also affect nausea or acid reflux.

Food patterns

Eating smaller more frequent meals, rather than three large meals, tends to work better with weight loss medication. Smaller portions are easier on the stomach when appetite is reduced, and steadier eating across the day helps your energy levels.

Keeping a food diary can be useful, especially if you are noticing side effects. Writing down what you eat, when, and how you feel afterwards often reveals a pattern (for example a specific food that triggers nausea) that you can then adjust.

Exercise

You do not need a gym routine to start with. Building movement into your week (walking, swimming, gentle strength work) supports the medication and helps you keep weight off, this can eventually build into something more substantial which will help with your habits when you eventually come off the medication. Aim for something most days rather than long sessions twice a week.

Common scenarios

• You feel nauseous after meals and are not sure why. Try smaller, more frequent meals and check your water intake first - because it slows down your digestive system, the acid in your stomach can sit there for longer and eventually become uncomfortable. Water can help neutralise it. 
• Your weight loss has slowed down. Reviewing your food, water and movement is the first step before considering a dose change - eating too little can slow your progress. 
• You feel tired or lightheaded. Low water intake is a common cause but this can also happen if you are not eating enough. 

When to get medical help

If you have severe or persistent symptoms, significant abdominal pain, persistent vomiting or signs of an allergic reaction, contact 999, your GP or NHS 111 rather than waiting. The guidance in this article covers everyday adjustments, not symptoms that need clinical attention.

What to do next

Start with the basics: track your water for a few days, keep a food diary with times. Add a daily walk if you are not already moving regularly. If side effects continue or get worse, contact us with details of your dose, how long you have been on it, and what you have noticed.

Still need help?

See our Contact us article for the best way to reach our team.