The Impact of Sugar, Processed Foods, and Alcohol on Preconception

Preparing for pregnancy involves more than just timing and tests—it begins with nourishing your body in a way that supports optimal fertility and long-term health for both parents. 

Nutrition plays a foundational role in hormone regulation, egg and sperm quality, and overall reproductive function. Among the key dietary factors to consider are the intake of added sugars, processed foods, and alcohol. Each of these can have a significant impact on preconception health, and understanding how they affect the body can help individuals and couples make informed choices on their fertility journey.

1. Added Sugars: Hormonal Imbalance and Insulin Resistance

Excessive intake of added sugars—found in soft drinks, sweets, flavoured yoghurts, and many packaged snacks—can disrupt the body’s hormonal balance and insulin sensitivity. High sugar intake contributes to elevated insulin levels, which in turn can lead to increased production of androgens (male hormones) in women. This hormonal imbalance is particularly relevant in individuals with polycystic ovary syndrome (PCOS), a leading cause of ovulatory infertility.

In men, high sugar consumption may be linked to lower sperm quality, motility, and testosterone levels (Salas-Huetos et al., 2017). Elevated blood sugar also contributes to systemic inflammation and oxidative stress—both of which can negatively impact fertility outcomes for both partners.

Tips to reduce added sugar:

• Opt for plain or unsweetened versions of yoghurt and nut milks.
• Choose whole fruits over fruit juices.
• Read labels for hidden sugars in sauces, dressings, and packaged foods.
• Limit overall intake of soft drinks, lollies, chocolates and other sweets and desserts.
  

2. Processed Foods: Nutrient Poor, Inflammatory, and Hormone Disrupting

Ultra-processed foods often contain a combination of added sugars, refined carbohydrates, unhealthy fats, artificial additives, and preservatives. Regular and excess consumption of these foods has been associated with chronic inflammation, metabolic dysfunction, and disrupted hormone signalling—all of which can impair reproductive function.

In addition, processed foods are also typically low in fertility-supporting nutrients such as folate, zinc, magnesium, and antioxidants. 

Studies have shown that individuals who consume more whole, minimally processed foods—such as vegetables, fruits, legumes, whole grains, and lean proteins—have better fertility outcomes and higher success rates in assisted reproduction (Gaskins et al., 2014).

Tips to reduce processed food intake:

• Cook at home more frequently using fresh ingredients.
• Opt for nuts, seeds, or whole fruit as snacks more often.
• Prep simple meals and snacks in advance to avoid last-minute processed options.

3. Alcohol: Egg Quality, Sperm Health, and Hormonal Effects

Alcohol intake, especially in excessive amounts, can negatively affect fertility in both men and women. In women, alcohol consumption may disrupt the menstrual cycle, increase time to conception, and impair ovulation (Tolstrup et al., 2003). It also reduces the absorption of key fertility nutrients such as folate and vitamin B6.

In men, alcohol can decrease testosterone levels, lower sperm count, and damage sperm morphology and motility. Long-term alcohol use has also been associated with increased DNA fragmentation in sperm, which can affect embryo quality and increase the risk of miscarriage (Martini et al., 2004).

There is no known "safe" level of alcohol when trying to conceive, and many health authorities recommend abstaining during the preconception period.

Tips to reduce alcohol intake:

• Try alcohol-free alternatives such as sparkling water with lime or alcohol-free wine/beer.
• Set alcohol-free days during the week and gradually build up.
• Replace the ritual of drinking with another relaxing habit, such as an evening walk or herbal tea.
  

In Conclusion

Reducing your intake of added sugars, processed foods, and alcohol is a powerful step toward improving fertility and creating a healthy foundation for conception and pregnancy. These dietary changes not only support hormone balance, egg and sperm quality, and nutrient absorption but also promote long-term health for both partners.

As you plan for pregnancy, focus on building a diet rich in whole foods, plenty of fibre, lean proteins, healthy fats, and fertility-enhancing nutrients. A registered dietitian can help guide you in making sustainable changes that align with your personal needs and goals.

References

1. Salas-Huetos, A., Bulló, M., & Salas-Salvadó, J. (2017). Dietary patterns, foods and nutrients in male fertility parameters and fecundability: a systematic review of observational studies. Human Reproduction Update, 23(4), 371–389.
2. Gaskins, A. J., Chavarro, J. E., et al. (2014). Dietary patterns and outcomes of assisted reproduction. The American Journal of Obstetrics and Gynecology, 210(4), 364.e1–364.e8.
3. Tolstrup, J. S., Kjaer, S. K., et al. (2003). Alcohol use as a predictor for infertility in a representative population of Danish women. BMJ, 327(7410), 505.
4. Martini, A. C., Molina, R. I., Estofan, D., Senestrari, D., Fiol de Cuneo, M., & Ruiz, R. D. (2004). Effects of alcohol and cigarette consumption on human seminal quality. Fertility and Sterility, 82(2), 374–377.