Managing Cancer-Related Weight Loss

Weight loss during cancer can feel worrying - and it's completely natural to feel concerned when you notice the numbers on the scale dropping. I want to reassure you there are many ways you can help manage this.

Let’s take a closer look at why cancer-related weight loss can happen - and what might help.

 

Why Does Weight Loss Happen During Cancer?

There’s rarely a single reason. Often, it’s a mix of factors. Some common causes I see in my clients include:

• Treatment side effects: like nausea, vomiting, digestive upset, and taste changes can make eating difficult or unappealing.

• Stress and anxiety: understandably, the emotional toll of cancer can affect appetite and eating habits.

• Fatigue: cancer-related tiredness can make shopping and preparing meals feel like a mountain to climb.

• Intentional changes: some people shift to healthier habits after diagnosis, which might result in weight loss.

• Fear around food choices: it’s common to feel unsure and restrict foods after reading or hearing conflicting advice.

• Metabolic changes: in some cases, cancer or treatment may affect how your body processes energy and maintains muscle. Your healthcare team can help you understand if this might be affecting you.

Understanding what’s behind your weight loss helps us co-create a nutrition approach that supports you.

Addressing Underlying Challenges

Before we explore what to eat, let’s talk about two key areas:

1. Managing symptoms - like nausea, taste changes, digestive issues, poor appetite, or fatigue. These can dramatically affect your ability to eat. You can find practical tips in this blog if you need support managing these.

2. Absorption and digestion – Some cancers and treatments affect how your body processes food and absorbs nutrients. This might be due to changes in your digestive system, hormone levels, or physical changes that affect eating. Your healthcare team can help identify and address any specific challenges you're experiencing.

Managing these early can make a big difference in how you feel - and how your body responds to food.

Nutritional Strategies to Manage Cancer-Related Weight Loss

1. Focus on Nutrient-Dense Foods in Smaller Portions

If large meals feel overwhelming, or you fill up quickly, try:

• Eating your biggest meal when you feel hungriest.

• Aiming for 5-6 small meals throughout the day.

• Establishing a routine by setting gentle reminders to eat if you often forget.

• Eating from a smaller plate or bowl to avoid feeling overwhelmed.

• Preparing nutrient-dense snacks in advance so they are easily accessible (e.g. overnight oats, chia seed pudding, yoghurt pots with berries).

2. Increase Protein Intake

Protein is important for maintaining muscle mass, supporting healing and repair, and bolstering the immune system. Consider:

• Adding extra meat, poultry, fish, tofu, beans, or lentils to soups and casseroles.

• Choosing protein-rich snacks like hard-boiled eggs, hummus with oatcakes, or Greek yoghurt with berries and a dollop of nut butter.

• Try adding protein-rich dairy products to your usual meals - like using milk instead of water when cooking porridge, adding Greek yoghurt to smoothies, or stirring cottage cheese into scrambled eggs.

• Incorporating protein powder into smoothies or porridge. You can find some more ideas here.

3. Omega-3 Fatty Acids and Muscle Mass

Especially for those who don't regularly consume oily fish, I might consider recommending an omega-3 fatty acid supplement. Recent research suggests that omega-3s, particularly from fish oil, may help maintain muscle mass in cancer patients experiencing weight loss. However, it is crucial to remember that all supplements, including omega-3s, must be discussed with and approved by your healthcare team before you start taking them. They can advise on whether this approach is suitable for you and ensure it doesn't interfere with your treatment plan.

Consider incorporating more omega-3 rich foods into your diet, such as oily fish (if you eat fish), walnuts, flaxseeds, and chia seeds.

4. Fortify Your Meals and Snacks

Add extra nourishment without significantly increasing volume by:

• Drizzling cold-pressed extra virgin olive oil or nut butter dressing (e.g. satay) over vegetables.

• Spreading avocado on sandwiches or adding it to smoothies.

• Adding grated cheese to scrambled eggs or soup.

• Sprinkling ground nuts or seeds over soups, cereals, or salads.

5. Choose Nourishing Fluids

Fluids are essential for hydration but can also provide calories and nutrients:

• Sip on drinks like vegetable juice, smoothies, or milkshakes made with your milk of choice.

• Enjoy small mugs of soup.

• Try warm drinks like milky coffee or milk with cinnamon, turmeric, or beetroot latte made with your choice of milk.

• Consider nutritional supplement drinks for added calories; some are available in supermarkets, chemists, or health food stores (e.g. Complan, Huel, or Naturya), or on prescription. Discuss options with your treatment team or GP; I can also help.

"But All I Fancy Is the Foods I ‘Shouldn’t' Be Eating"

This is a common concern I hear from clients: “But all I fancy is ice cream, crisps, or chocolate.”

When your appetite is poor, it's important to focus on what you can manage to eat without adding extra stress or guilt about food choices. Eating what appeals to you matters. My clients know I prefer focusing on what we can ADD rather than what to subtract. Pairing foods with other nourishing options can help create a balanced meal or snack.

Together, we can find nourishing ways to gently build on those foods, for example:

• Ice cream: add fresh or frozen berries to vanilla ice cream for a homemade raspberry ripple. Sprinkle nuts or seeds on top for extra protein and beneficial fats.

• Chocolate bar: break up chocolate into a jar and mix with any combination of nuts, seeds, coconut curls, or dried fruit for a nourishing trail mix.

• Crisps: try chickpeas or edamame beans roasted with miso, tamari, or paprika.

• Cola: if it's the sparkling fluid you're craving, pair sparkling water with your favourite fruit juice, or ginger or elderflower cordial. Depending on your needs, I might also suggest adding electrolytes to your drink.

This is a time to take pressure off - and meet your body where it is.

“Can I Still Lose Weight If I Wanted To Before?”

This question comes up frequently in my cancer nutrition workshops. "Can I still try to lose a bit of weight during treatment?" And like many things in cancer nutrition, there isn't a set answer - it depends on the individual.

In some treatments, such as head and neck radiotherapy, maintaining weight is essential. Significant weight loss could lead to treatment interruptions or re-planning. For others, especially those on long-term treatments with weight to lose, gentle weight loss through sustainable habits may be okay -  if you’re feeling well, strong, and staying in a healthy range.

What matters most is avoiding rapid weight loss - which often results in losing muscle, not just fat. Maintaining muscle helps you stay strong, tolerate treatment better, and recover faster.

Your treatment team can guide you on what is best in your specific situation.

Movement Also Matters

Moving your body in a way that feels right for you is an important part of your care, alongside good nutrition. Research shows that physical activity is safe and beneficial for most people before, during, and after cancer treatment. You can find advice on physical activity during cancer treatment from my trusted physiotherapy colleagues here.

You Don’t Have to Figure This Out Alone

Unintentional weight loss can feel unsettling - especially when you’re already coping with so much. It’s something I support people with all the time, and I’d be delighted to help you too.

Together, we can:

• Understand what’s contributing to your weight loss

• Ease symptoms that are getting in the way of eating

• Make food feel simpler, more nourishing, and less stressful

• Build a plan that meets you where you are, and adapts with you

If you're not sure where to start, I’d be happy to help you find the way forward.

📩 info@thecancerdietitian.com

☎️ 020 8064 2865

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The content provided in this blog is for informational purposes only and should not be considered personalised nutrition, dietetic, or medical advice. Please consult your healthcare team for personalised advice and guidance regarding your specific medical condition or dietary needs.