When Is the Best Time to Focus on Cancer Nutrition?

When someone makes an enquiry with my office, one question that sometimes comes up is:

“Should I wait?”

Should I wait until after my chemotherapy?

Until after radiotherapy?

Until after surgery?

Until things have settled down

Until I’ve got more headspace to focus on this?

It’s a very reasonable question, and it usually comes from people who are highly motivated and want to approach their nutrition in a way that gives them the best chance of getting it right.

When I’m asked, my answer is always the same:

No, you don’t need to wait - and in fact, the sooner you start, the better.

The evidence is clear that starting sooner can make a meaningful difference to how well people manage treatment, support treatment tolerance, and contribute to better recovery.

Why Nutrition Isn’t Something to ‘Come Back to Later’

Waiting to focus on nutrition can mean missing a valuable window to put steady foundations in place - foundations that make a real difference to how you feel and function during treatment.

And nutrition isn’t just helpful at the beginning. It becomes part of how you manage symptoms and stay resourced through the different phases of treatment. Many people don’t realise how much practical difference this can make.

Starting earlier isn’t about doing more, it’s about giving yourself every possible advantage.

Why You Don’t Need a ‘Perfect Moment’ to Begin

People sometimes imagine they need to be more settled, more focused, or more "ready" before starting nutrition support so they can give it "proper attention".

But it doesn't work like that. There isn't a 'big switch to flip', no overhaul to brace for, and no expectation that you suddenly do things differently overnight. Good nutrition support meets you exactly where you are - preparing for treatment, in the middle of it, in a busy week, in uncertainty, or on a day when your energy is low.

The guidance adapts to your symptoms, your routines, your capacity, and your life. For many people, the most sustainable changes are small and steady. For others, bigger shifts feel right, and that can be supported too.

The point is that it is not a start–stop process. It is supportive, flexible, and paced with you, not layered on top of everything else.

The evidence for early cancer nutrition support is strong

Prehabilitation (often called prehab) means getting ready for cancer treatment in the time you have before it begins. It focuses on strengthening your nutrition, movement, and emotional wellbeing so you feel as well supported as possible when treatment starts.

The evidence around prehabilitation continues to grow. Preparing early really can make a difference. Cancer Research UK describes how people taking part in prehab are more likely to:

• leave hospital sooner after cancer surgery

• cope better with the side effects of treatment

• experience fewer side effects

• have more treatment options

• have better long-term health

These are not small gains. They’re meaningful shifts in how people move through treatment and recover afterwards.

Starting these conversations earlier gives us more scope to address any gaps and optimise nutritional status ahead of treatment. It’s one of the reasons I encourage people not to delay these discussions when they’re considering getting started.

What people tell me after starting to focus on their nutrition early

People who begin focusing on their nutrition before treatment often tell me afterwards how helpful it was to have had that window to get a few things in place. Having a clear plan helped them feel calmer and better resourced as treatment began.

People say these things:

• “I felt more prepared and less overwhelmed.”

• “It helped me understand what to expect, and what I didn’t need to worry about.”

• “I felt more confident going in.”

• “All the information and attuned advice you’ve been offering me so far is tremendously helpful - I’m much more consciously and skilfully navigating this challenging time.”

If you’d like some nutrition tips to support you before treatment begins, you may find this blog helpful: Nutrition Tips for Cancer Prehabilitation.

During Treatment: Why Nutrition Support Can Make A Real Difference

 A closer look at the AICR guidance:

The American Institute for Cancer Research puts this clearly. Their infographic states:

“From day one, nutrition should be considered alongside treatment for improved outcomes.”

They also highlight that after a cancer diagnosis, eating well can help you throughout chemotherapy, radiotherapy, and surgery. In other words, nutrition isn’t something to delay. It plays a supportive role right from the start and throughout treatment.

AICR also outlines several ways good nutrition can help during treatment, including supporting:

• faster healing and recovery

• strength and energy

• immune function

• your ability to tolerate treatment

• maintaining a healthy weight

• replacing or retaining nutrients

• reducing your risk of infection

• and contributing to long-term health outcomes

This reflects what I consistently see in practice - early nutrition support can make a profound difference.

And while our conversations centre on food, they naturally touch on other areas too: routines, rest, small moments that support your nervous system, and ways to bolster your overall wellbeing. It’s never just about nutrition - it’s about supporting the whole you.

When people consider postponing is often when support helps most

People sometimes consider delaying their appointment because they’re struggling to eat “well” or feel they’ve gone off track, or they have symptoms like nausea or looser stools. If you’re acutely unwell, rest is always the priority.

But delaying because you’re not eating ‘perfectly’ is something different, and it’s often the moment when support can make the most difference.

Nutrition guidance at these times can help you:

• find what’s possible from where you are

• get nourishment on board without worsening symptoms

• reduce the mental load

• protect hydration

• ease symptoms

• feel more able to cope

• feel better sooner

It takes away that sense of “how on earth do I manage this now?” and replaces it with clear, manageable steps.

If you're looking for practical tips to help manage treatment side effects, this blog may help: A Practical Guide to Managing Cancer Treatment Side Effects.

Nutrition Can Support You At Any Stage

Wherever you are in your care - preparing, in the middle of treatment, early recovery, or months or years later - nutrition doesn’t require perfect conditions or a “right time”.

It starts from where you are.

Not waiting until things feel more settled.

Not waiting until you feel your best.

Not waiting until the end of treatment.

Nutrition support often makes the biggest difference when it begins from your real starting point, wherever that is today.

If You’d Like Personalised Support

If you’d value clearer direction with your nutrition, at your pace, you’re welcome to get in touch.

Written by Meredy Birdi, a dual-qualified oncology dietitian and nutritional therapist specialising in supporting people affected by cancer.

This blog is for general information only and is not a substitute for individual medical or dietetic advice.