Diet and Nutrition — While on Trastuzumab

If trastuzumab is your only treatment, food safety rules are much less strict than during chemotherapy. The general advice applies — food that is freshly made and served hot is safer than food that has been sitting out. If you are also receiving chemotherapy as part of your regimen, the stricter food rules apply during those cycles. Tell your oncology team exactly what your treatment plan involves so they can give you guidance specific to your situation.

No, and cutting out all sugar is unnecessarily restrictive and hard to sustain when your appetite is already affected. ASCO nutrition guidance focuses on reducing heavily processed sugars — packaged sweets, cold drinks, and very sweet desserts — not on eliminating sugar from a normal diet. Jaggery, fresh fruit, and a small amount of honey in chai are all reasonable. A very high-sugar diet is worth reducing because it can contribute to weight changes that affect treatment, but strict elimination is not evidence-based and often makes eating miserable.

Try small amounts frequently rather than forcing a full plate. Not eating for long periods affects your energy and your body's ability to manage treatment. Start with something easy — a small bowl of khichdi, curd rice, or dal — rather than a meal that feels overwhelming. If your appetite is very poor for more than a few days, tell your oncology team. A dietitian referral, or a review of whether something in the treatment is causing it, may help. Poor appetite that continues is a symptom worth reporting, not something to manage alone.

Some are safe and some are not, and there is no way to know without your oncology team reviewing what you are taking. Several common Ayurvedic preparations contain compounds that affect how the liver processes drugs, which can change how your treatment works or worsen side effects. Tell your oncologist about everything — supplements, tonics, herbal teas, and traditional preparations. Most oncologists will not ask you to stop everything. The concern is specific interactions, not the tradition itself.

Yes, and it is worth reporting to your team rather than accepting it as inevitable. Unintentional weight loss can affect your strength, how your body tolerates treatment, and sometimes reflects a change your team needs to assess. In the meantime, try adding small amounts of higher-calorie, protein-rich food — full-fat curd, a spoonful of peanut butter, a small handful of nuts, or full-fat milk stirred into dal or khichdi. A dietitian referral can help identify why it is happening and what specifically to do.