Ultra-Processed Foods and Fertility: What the Research Really Shows

What Are Ultra-Processed Foods?

Ultra-processed foods are industrial formulations made mostly or entirely from substances derived from foods and additives, with little if any intact whole food¹. They typically contain ingredients you wouldn't find in a home kitchen – emulsifiers, hydrogenated oils, modified starches, and flavour enhancers.

Common examples include:

• Soft drinks and energy drinks
• Packaged snacks (crisps, biscuits, confectionery)
• Ready meals and instant noodles
• Processed meats (sausages, nuggets, burgers)
• Mass-produced breads and breakfast cereals
• Flavoured yoghurts and dairy desserts

For evidence-based nutritional guidance for fertility, see our comprehensive guide: Dissecting the Fertility Diet: Evidence-Based Nutritional Recommendations.

The Research: UPFs and Female Fertility

Several studies have now linked high ultra-processed food consumption to fertility challenges in women:

Ovulatory Disorders

Research from the Nurses’ Health Study II found that women with higher intakes of trans fats (commonly found in UPFs) had a 73% higher risk of ovulatory infertility². Trans fats can promote inflammation and insulin resistance, both of which interfere with ovulation.

IVF Outcomes

A recent study showed that women who consumed more ultra-processed foods had lower rates of clinical pregnancy and live births³. The researchers suggested that additives and lower nutritional quality might contribute to poorer outcomes.

Learn more about nutritional strategies for IVF in our article: Nutrition to Boost IVF Success.

UPFs and Male Fertility

Men are not immune to the effects of ultra-processed foods on fertility:

Sperm Quality

Studies have shown that men with higher UPF consumption tend to have lower sperm counts, reduced motility, and more abnormal sperm morphology⁴. The combination of oxidative stress from poor nutrition and direct effects of food additives may be responsible.

Hormonal Effects

Many UPFs contain compounds that can act as endocrine disruptors, potentially affecting testosterone levels and overall reproductive function⁵.

Read more about factors that may affect male conception: Could These Four Things Be Hindering Your Chances of Conception?

How UPFs Affect Fertility

Research suggests several pathways through which ultra-processed foods may impact fertility:

Inflammation

Many UPFs promote chronic low-grade inflammation, which can interfere with ovulation, implantation, and sperm function⁶.

Oxidative Stress

Low antioxidant content combined with pro-oxidant additives can increase oxidative damage to eggs and sperm. For information on combating oxidative stress, see: The Impact of Oxidative Stress on Fertility.

Blood Sugar Dysregulation

High sugar content and refined carbohydrates can cause blood sugar spikes and insulin resistance, disrupting hormonal balance.

Nutrient Displacement

When UPFs make up a significant portion of the diet, they often replace more nutritious whole foods that provide essential fertility-supporting nutrients.

Making Better Food Choices

If you're trying to conceive, consider these practical swaps:

• Choose whole grain bread over sliced white bread
• Opt for plain yoghurt with fresh fruit instead of flavoured varieties
• Prepare simple meals from scratch when possible
• Read labels – if a product contains more than 5 ingredients or ingredients you don't recognise, it's likely a UPF
• Increase intake of colourful vegetables, fruits, nuts, and legumes

For more guidance on diet and fertility, explore: Why Is Diet Important for Fertility?

Supporting Your Body with Targeted Nutrition

While reducing UPFs is important, ensuring adequate intake of key fertility nutrients can help offset some dietary challenges:

Essential Vitamins and Minerals

A comprehensive fertility supplement like Vitafem for women or Vitamen for men can help ensure you're getting adequate levels of folate, zinc, selenium, and other fertility-supporting nutrients that may be lacking in a diet high in processed foods.

Antioxidants

Antioxidants help protect eggs and sperm from oxidative damage. For women, we recommend Zita West Vitafem Boost, a premium antioxidant formula providing Vitamins A, C and E to protect egg quality, support immune function and enhance your fertility journey.

For men, we recommend Zita West Vitamen Boost, a complex of well researched antioxidants designed to combat oxidative stress.

Omega-3 Fatty Acids

These healthy fats support hormone production and reduce inflammation. Vital DHA provides high-quality omega-3s in their most bioavailable form.

Frequently Asked Questions

How much processed food is too much when trying to conceive?

While there's no definitive threshold, research suggests that fertility outcomes improve when UPFs make up less than 20% of daily calories. Focus on gradually replacing processed options with whole food alternatives rather than aiming for perfection.

Are all processed foods bad for fertility?

Not all processing is problematic. Minimally processed foods like frozen vegetables, tinned beans, or natural cheese retain their nutritional value. The concern is specifically with ultra-processed foods that contain numerous additives and have little resemblance to their original ingredients.

Can I reverse the effects of a high-UPF diet?

Yes, dietary changes can have relatively quick effects on markers like inflammation and blood sugar control. Sperm quality may improve within 2-3 months of dietary changes, while egg quality improvements may take longer but are still possible.

What about ready meals – are they all harmful?

Ready meals vary widely. Look for options with short ingredient lists featuring recognisable foods, minimal additives, and lower sodium content. Better still, batch cook your own meals when time allows.

Do supplements compensate for a poor diet?

Supplements can help fill nutritional gaps but cannot fully compensate for a poor diet. They work best as part of an overall healthy eating pattern. Focus on improving your diet while using supplements to ensure optimal nutrient intake.

This information is intended for general educational purposes. For personalised dietary advice, please consult a registered dietitian or your healthcare provider.

References

1. Monteiro CA, et al. Ultra-processed foods: what they are and how to identify them. Public Health Nutr.
2. Chavarro JE, et al. Dietary fatty acid intakes and the risk of ovulatory infertility. Am J Clin Nutr. 
3. Kellow, N, J, et al. The Effect of Dietary Patterns on Clinical Pregnancy and Live Birth Outcomes in Men and Women Receiving Assisted Reproductive Technologies: A Systematic Review and Meta-Analysis. Adv Nutr.
4. Mendiola J, et al. Food intake and its relationship with semen quality. Fertil Steril.
5. Nassan FL, et al. Diet and men's fertility. Fertil Steril.
6. Calder PC. Omega-3 fatty acids and inflammatory processes. Nutrients.