Preview for Kara’s review. Educational draft · clinical approval pending.
Lifestyle advice for fertility is everywhere online, and much of it is either alarming or overpromising. The evidence supports a few clear, sensible steps, and they apply to both partners.
No single food, habit or routine has been proven to produce a pregnancy. But a handful of changes are well supported, and making them together as a couple is often easier than going it alone.
Smoking
Smoking is one of the clearest lifestyle factors to change, for both partners. In women, smoking is likely to reduce fertility, and breathing in other people’s smoke (passive smoking) is likely to affect the chance of conceiving too. In men, smoking is linked with lower sperm count, movement and shape. The World Health Organization’s fertility guideline strongly recommends brief advice to stop for everyone who uses tobacco, so it’s worth asking your healthcare professional for help. In South Africa, the National Council Against Smoking runs a Quitline on 011 720 3145.
Alcohol
Because you may not know you’re pregnant for several weeks, the safest approach while you’re trying to conceive is not to drink alcohol at all. If you drank a little before you knew you were pregnant, try not to worry: the risk from small amounts is likely to be low. South Africa has one of the highest rates of fetal alcohol spectrum disorder in the world, and it is completely preventable. Heavier drinking is also linked to lower fertility in women and to poorer sperm quality and IVF results in men, so cutting down is a sensible step for both partners.
Caffeine
Moderate caffeine does not appear to reduce your chance of getting pregnant, naturally or with IVF. It is still wise to keep it modest: higher intakes are linked to a higher risk of miscarriage, and UK advice in pregnancy is no more than 200 mg of caffeine a day (a cup of instant coffee has about 100 mg). The amount of caffeine in a cup varies a lot, so check your usual drinks. For men, the caution is about very high intake and energy drinks or sodas rather than coffee itself.
Weight
A higher BMI is linked with taking longer to conceive, and being underweight is too, to a smaller degree. If your BMI is 30 or over and you aren’t ovulating, losing weight is likely to improve your chance of conceiving; if it is under 18.5 and your periods are irregular or absent, gaining weight is likely to help. Programmes that combine exercise and dietary advice work better than weight-loss advice alone. Weight is something to discuss and get support with, not something to blame yourself for.
Food, exercise and sleep
A Mediterranean-style way of eating has been associated with better fertility outcomes in observational studies. It is a healthy pattern, though no diet has been proven to treat infertility. Regular, moderate exercise is good for you and is linked to better fertility for both women and men; very intense exercise has been linked to slightly lower fertility in some studies. Short sleep has been linked to slightly lower fertility too, but the evidence is limited.
For men
European urology guidance advises that obesity, low physical activity, smoking and heavy drinking can lower sperm quality and testosterone. Higher scrotal temperature is linked with poorer semen quality, but it’s uncertain whether loose underwear helps. After anabolic steroids are stopped, sperm usually improve over 6 to 12 months.
Myth vs evidence
“You have to give up coffee completely to get pregnant.”
Moderate caffeine doesn’t appear to reduce the chance of conceiving. Keeping it modest is still wise, mainly because of miscarriage risk at higher intakes.
“There’s a fertility diet that will get you pregnant.”
Healthy eating patterns are associated with better outcomes, but no diet has been proven to treat infertility.
“Lifestyle only matters for the woman.”
Smoking, heavy drinking and weight affect sperm too. Changes are easier, and fairer, when both partners make them.
- Is there anything in our lifestyle you would change first?
- Would support with weight be helpful for me, and what is available?
- Where can I get help to stop smoking?
- Could any chemicals I work with affect fertility or pregnancy?
Words you may hear
- BMI
- Body mass index: weight in kilograms divided by height in metres squared. A rough screening measure, not a measure of health.
- Fecundability
- The chance of conceiving in a single menstrual cycle.
- Fetal alcohol spectrum disorder (FASD)
- A range of lifelong conditions caused by alcohol exposure before birth. It is completely preventable.
A few well-supported changes, made together, are worth more than any “fertility diet”.
Watch with Kara
Videos on this topic are coming to the channel:
- Fertility Nutrition: Evidence vs Online Claims
- Exercise and Fertility
- Lifestyle and Fertility: What the Evidence Says
- Alcohol, Caffeine and Trying to Conceive
- Sperm Health: Changes Partners Can Make
Male fertility belongs in the same conversation. These illustrated guides pair with this topic:
Want the foundations in one place? The free Fertility Starter Guide covers ten things everyone should understand about their fertility.
Sources 9 studies and guidelines Show the research
- World Health Organization (2025). Guideline for the prevention, diagnosis and treatment of infertility.
- NICE (2026). Fertility problems: assessment and treatment (guideline NG257).
- National Department of Health, South Africa (2024). National integrated maternal and perinatal care guidelines, 5th edition.
- ASRM Practice Committee (2022). Optimizing natural fertility: a committee opinion. Fertility and Sterility.
- ASRM Practice Committee (2021). Obesity and reproduction: a committee opinion. Fertility and Sterility.
- Minhas et al. (2025). European Association of Urology guidelines on male sexual and reproductive health: 2025 update on male infertility. European Urology.
- UK Chief Medical Officers (2016). Low risk drinking guidelines.
- Lyngsø et al. (2017). Coffee or caffeine consumption and fecundity and fertility: a systematic review and dose-response meta-analysis. Clinical Epidemiology.
- Alesi et al. (2023). Assessing the influence of preconception diet on female fertility. Human Reproduction Update.