A new 2026 study is drawing attention to a surprisingly simple question: could what you eat while taking antibiotics affect how much the treatment disrupts your gut microbiome?

Researchers from NYU Langone Health and collaborating institutions found that sugar-rich foods were associated with greater disruption of the gut's microbial community during antibiotic treatment.

Why Does the Gut Microbiome Matter?

The gut microbiome is the enormous community of microorganisms living throughout the digestive tract. These organisms are involved in digestion, metabolism and interactions with the immune system.

Antibiotics are designed to eliminate harmful bacteria, but they can also reduce helpful bacterial populations. That temporary loss of diversity can change the balance inside the gut.

What Did the New Study Find?

The researchers examined detailed food records from 173 hospitalized cancer patients, covering 9,419 meals, and compared dietary patterns with changes in the gut microbiome.

The study found that higher sugar exposure during antibiotic treatment was linked with greater microbiome disruption and increased growth of potentially harmful bacteria.

Does This Mean You Must Avoid All Sugar?

No. The research does not mean that eating one dessert while taking an antibiotic will automatically cause harm.

It also does not establish that cutting sugar will prevent every antibiotic-related microbiome problem. The researchers themselves indicate that further clinical research is needed.

The practical takeaway is much more moderate: if you're taking antibiotics, it may be sensible to avoid making a high-sugar diet your default while your gut microbiome is already under stress.

What Could a Balanced Approach Look Like?

• Follow your prescribed antibiotic schedule exactly.
• Stay adequately hydrated unless your doctor has given you fluid restrictions.
• Prioritize a varied diet rather than relying heavily on sweets and ultra-processed foods.
• Ask your doctor or pharmacist whether particular foods, supplements or probiotics are appropriate with your medication.
• Do not stop antibiotics early because of concerns about gut health.

The Bigger Lesson

The study is another reminder that health is rarely about one isolated food or one isolated habit. Medication, diet, sleep, stress and the microbiome can interact in complicated ways.

For now, the strongest conclusion is not “sugar is dangerous during antibiotics.” It is that diet may influence how the gut responds to antibiotic treatment, and researchers need more evidence to determine exactly how clinicians should use that information.

Health note: This article is for general information and does not replace medical advice. If you are taking antibiotics, follow your healthcare professional's instructions.

Research source: NYU Langone Health / Nature, 2026.