Diet and Lifestyle for Fertility: What the Evidence Actually Supports
Key takeaways
- The lifestyle changes with the best evidence are reaching a healthy weight, stopping smoking, limiting alcohol and caffeine, and (for the woman) taking folic acid before conceiving.
- Folic acid is about preventing neural tube defects in the baby, not about boosting fertility; the usual advice is 400 micrograms daily from before conception until 12 weeks of pregnancy.
- Smoking is linked to reduced fertility in both partners and stopping is one of the clearest, most useful steps a couple can take.
- Many popular fertility diets, supplements and superfoods are not backed by strong evidence; be cautious about anything promising to boost your chances.
- Lifestyle helps at the margins, but it does not undo age or a medical cause, so do not delay seeing your GP or fertility team if you are concerned.
The diet and lifestyle changes with real evidence behind them are reaching a healthy weight, stopping smoking, limiting alcohol and caffeine, and taking folic acid before you conceive. Almost everything else marketed as fertility-boosting is unproven. When we were trying, I wasted months chasing supplements and superfoods; what actually mattered was the short, dull list the NHS gives for free. Here is what the evidence supports, and what it does not.
What the evidence actually supports
A handful of changes are genuinely worth making, because they are backed by guidance from the NHS, NICE and the American Society for Reproductive Medicine rather than by marketing. The honest framing is that these help at the margins and support a pregnancy once it happens; they are not a cure for a medical cause and they cannot reverse the effect of age on fertility. Think of them as stacking the odds slightly in your favour while you get properly assessed.
A healthy weight
Reaching a healthy weight is the single most evidence-backed thing many couples can do. Being significantly overweight or underweight can disrupt ovulation, and NICE notes that a woman with a body mass index above 30 is likely to take longer to conceive. Excess weight in men is linked to reduced sperm quality too, so it is worth both partners thinking about. The aim is steady, sustainable change rather than crash dieting; even modest weight loss can help if your BMI is high. This is one of the clearest ways diet and lifestyle feed into trying to conceive.
Stopping smoking
Stopping smoking is one of the most useful steps either partner can take. Smoking is associated with reduced fertility in women and with lower sperm quality in men, and the NHS lists it among the key things to address before pregnancy. It is also linked to a higher risk of miscarriage. There is no safe level, so cutting down matters less than stopping; your GP can refer you to free NHS stop smoking support, which roughly triples your chance of quitting for good compared with willpower alone.
Alcohol and caffeine
Limiting alcohol and caffeine is sensible, with the strongest advice applying once you are pregnant. The NHS is clear that there is no known safe amount of alcohol in pregnancy, so many couples stop drinking as soon as they start trying; heavy drinking is linked to reduced fertility in both partners. For caffeine, the official limit in pregnancy is 200 milligrams a day, about two mugs of instant coffee, counting tea, cola and chocolate too. The evidence that moderate caffeine harms fertility itself is weaker, but keeping intake modest costs nothing and removes one worry.
Folic acid and supplements
Folic acid is essential, but not for the reason many people assume. Taking 400 micrograms a day from before conception until 12 weeks of pregnancy lowers the risk of neural tube defects such as spina bifida in the baby; it does not improve your chance of getting pregnant. Some women, including those with diabetes or a higher BMI, are advised a higher dose, so check with your GP. Beyond folic acid (and vitamin D, which the NHS recommends in pregnancy), most fertility supplements lack good evidence. I had a drawer full of expensive pills; the only one my doctor actually cared about was the cheap folic acid.
What the evidence does not support
Be cautious about anything that promises to boost fertility, because much of it is not backed by strong research. Specific superfoods, detoxes, expensive multi-supplement stacks and elimination diets are largely unproven for conception, and the ASRM is careful not to overclaim here. That does not make a balanced, Mediterranean-style diet pointless; it supports your general health and a healthy weight, which is the part that genuinely matters. The risk is spending money and emotional energy on the unproven while delaying assessment of a real, treatable cause.
When lifestyle is not the answer
Lifestyle changes are worth making, but they are not a substitute for medical assessment. They cannot fix blocked tubes, severe male factor infertility, or the steady decline in fertility that comes with age, and they should never be a reason to wait. If you have been trying for a year, or six months if the woman is over 36, or if you have a known reason to be concerned, see your GP rather than relying on diet alone. Our guide on when to see a doctor about fertility explains the timelines, and the causes of infertility are worth ruling out alongside any lifestyle changes.
This is general information and support, not medical advice. For guidance on your own situation, including the right doses and any tests you may need, please speak to your GP or a fertility specialist.
References
- Trying to get pregnant, NHS.
- Fertility: assessment and treatment for people with fertility problems (CG156), National Institute for Health and Care Excellence (NICE).
- Vitamins, supplements and nutrition in pregnancy, NHS.
- Optimizing Natural Fertility, American Society for Reproductive Medicine (ReproductiveFacts.org).
Frequently asked questions
What is the best diet for fertility?
There is no single proven fertility diet. The strongest evidence supports a generally healthy, balanced diet that helps you reach and stay at a healthy weight, rather than any specific superfood or supplement. A Mediterranean-style pattern (plenty of vegetables, fruit, wholegrains, fish and olive oil) is often suggested because it supports overall health, but it is not a guaranteed fertility boost. Be wary of diets or supplements that promise to dramatically increase your chances.
Does losing weight improve fertility?
For people who are overweight or underweight, moving towards a healthy weight can help. Being significantly above or below a healthy weight can disrupt ovulation and is linked to lower success with fertility treatment, and excess weight in men is associated with reduced sperm quality. NICE notes that a body mass index above 30 can reduce a woman's chance of conceiving. Even modest, sustainable changes can make a difference, but crash dieting is not advised.
Do I need to stop drinking alcohol completely to get pregnant?
Once you are pregnant, the safest approach is to avoid alcohol entirely. While you are trying to conceive, the NHS advises limiting alcohol, and there is no known safe amount in pregnancy, so many couples choose to cut it out once they start trying. Heavy drinking is linked to reduced fertility in both partners. If you are unsure, your GP can give advice tailored to you.
How much caffeine is safe when trying to conceive?
Official advice focuses on pregnancy, where the NHS recommends limiting caffeine to no more than 200 milligrams a day (roughly two mugs of instant coffee). The evidence that caffeine harms fertility itself is weaker and mixed, but keeping intake moderate while trying is a sensible, low-cost step. Remember caffeine is also in tea, cola, energy drinks and chocolate.
When should I start taking folic acid?
Start folic acid as soon as you are trying for a baby, ideally before you conceive, and continue until 12 weeks of pregnancy. The standard dose is 400 micrograms a day. Folic acid does not improve your chances of conceiving; it lowers the risk of neural tube defects such as spina bifida in the baby. Some people, including those with diabetes or a higher BMI, are advised a higher dose, so ask your GP.
Can lifestyle changes alone fix infertility?
Not usually. Lifestyle changes can support your overall fertility and improve your odds with treatment, but they cannot reverse age-related decline or treat an underlying medical cause such as blocked tubes, severe male factor infertility or PCOS on their own. They work best alongside, not instead of, proper assessment. If you have been trying for a year (or six months if the woman is over 36), see your GP.
Written by Emma Lawson. Medically reviewed by Dr Priya Nair, MBBS, MRCOG.
Our guides are written from personal experience and reviewed by a qualified clinician for accuracy. Read our editorial policy.