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Which Is The Best Fertility Diet?

I know you probably have tried to go on a diet in the past, mainly for weight loss. But when it comes to fertility diet, not all diets are created equal and give you the outcome that you want, which is to get pregnant ultimately.

Diet impacts fertility, and specific nutrients and food groups appear to affect reproductive health positively. However, there is still no official nutrition guidelines on how you should eat.

In today’s blog post, I share:

  1. The pros and cons of these three dietary approaches based on the current evidence
  2. The success that these diets had to help women getting pregnant
  3. How to choose the right diet if you’re thinking about trying to conceive

If you’re unsure which type of diet would work best, this will be the starter guide for you!

1. Mediterranean Diet

A Mediterranean diet emphasises higher plant-foods intake like fruits, vegetables, whole grains, legumes, and healthful fats from olive oil, nuts and seeds—a moderate amount of white and red meat, fish, dairy and eggs consumption. Alcohol, predominantly red wine, is included in a Mediterranean diet but only consumed in low to moderate amounts with meals. 

The evidence of Mediterranean eating patterns on reducing the risk of heart disease, type 2 diabetes and cancer are well documented. The Mediterranean diet has been shown to support weight loss and weight maintenance due to its beneficial antioxidants, anti-inflammatory effects, and gut health. 

To date, no randomised control trials or systematic reviews (highest levels of evidence) have investigated the effectiveness of a Mediterranean diet on fertility and reproductive outcomes in women. Two studies have shown beneficial effects so far. 

In a cohort study by Karayiannis et al. published in 2018, the researchers followed 244 women (aged between 22 – 41 years; BMI < 30 kg/m2) who underwent a first IVF treatment in Greece) and studied their dietary intake and lifestyle on fertility outcomes. They found that 50% of women who follow the Mediterranean eating pattern (defined by the MedDietScore, MDS) had successfully got pregnant and live births, compared to only 29% for those who scored lower on MDS.

The authors also found that among women <35 years, a beneficial 5-point increase in the MedDietScore was associated with ~2.7 times higher likelihood of achieving clinical pregnancy and live birth. There is no association between Mediterranean eating patterns and outcomes such as oocyte yield, fertilisation rate, and embryo quality. 

Another study from Gaskins et al. followed 357 mostly Caucasian women who underwent assisted reproductive technologies (ART) in the US. The researchers found that adherence to the Mediterranean diet was associated with an increased chance of implantation, clinical pregnancy and live birth. Interestingly, the authors also hypothesised that pesticides on food products could also impact the fertility rate. 

The Bottom Line:

If you’re under the age of 35 years and your BMI is under 30, following a Mediterranean diet may improve IVF outcomes and the success rate of having a baby.

While there is no current evidence supporting this approach in older women or women with a BMI above 30, following the Mediterranean diet may be advantageous if combined with weight reduction strategies.

Mediterranean diet has also been shown to enhance the sperm quality in men, and thus for couples with unexplained fertility, adherence to the Mediterranean Diet may help. 

2. Low-Carbohydrate Diet

While there is no strict definition of how low the carbohydrate intake would be on a low-carb diet, anything under 150 grams per day is generally considered low-carb or if it’s less than 45% of total energy intake. You are likely to also hear about the ‘keto diet’. The ketogenic diet describes as a ‘very low-carb diet, where the total carbohydrate intake reduces to less than 50g per day or less than 10% of total energy intake for the body to get into ketosis. 

A recent systematic review examined seven studies on the effects of low-carb diets on reproductive outcomes in overweight and obese women with diagnosed infertility (defined as BMI above 25). The study found that reducing the carb intake, in conjunction with a moderate calorie reduction, can reduce the circulating insulin levels, improve hormonal imbalance and resume ovulation to improve pregnancy rate compared to the usual diet, particularly for overweight and obese women with PCOS.

There is no clear indication of whether the low-carb diet is effective for women without PCOS. It is also unclear how low the carb should be or how long the diet optimises fertility outcomes. 

Fertility Diet Challenge

The Bottom Line:

If you’re currently struggling with losing weight with a BMI over 25, following a low-carb diet with a caloric-controlled diet may be one of the approaches to reduce body weight and improve fertility outcomes.

I would recommend consulting a fertility dietitian like myself before going on a low-carb diet to ensure that you’re still getting enough pregnancy nutrients, especially folate and iodine and helping you choose the right supplement accordingly.

It is also important to note that you should cease any strict weight loss diet or a very low caloric diet (preferably six weeks before a fertility treatment) or once you’re pregnant).

3. Intermittent Fasting 

Intermittent fasting

Intermittent fasting has been gaining popularity as an alternative strategy for achieving and maintaining weight reduction. It is not a diet per se, but it involves alternating between periods of fasting.

An example of an intermittent fasting regimen includes the 5:2 diet, which involves two non-consecutive fasting days every week. And another popular regimen is the 16:8, whereby food is consumed within an 8-hour window, followed by a 16-hour fast. Another typical example is during the Ramadan fasting period, Muslims fast the entire month from dawn to sunset for spiritual reasons.

No studies are investigating the effects of the IF approach on fertility in men and women. However, two recent systematic reviews and meta-analyses have shown positive effects on weight loss and varying cardiometabolic health effects.  

Cho et al. (2019) analysed 12 studies involving 545 participants compared to a regular diet or a continuous energy restrictive diet. They found that IF led to a significant reduction in BMI, fasting glucose levels and insulin resistance. 

Another study from Schwingshack et al. (2020) included 17 high-quality studies with 1328 participants that again compared IF to a regular diet or a continuous energy restrictive diet. The authors found that IF significantly reduces body weight, waist circumference, body fat mass, blood triglycerides level, and blood pressure compared to a regular diet. However, no difference between the effects of IF and a restrictive energy diet means the health outcomes are the same whether or not you follow an IF diet v.s. Caloric-reduction diet.

The Bottom Line:

To date, no evidence supports IF to improve fertility outcomes in men and women. However, IF appears to affect weight reduction positively and may also improve insulin sensitivity, which are the critical steps in optimising fertility and balancing the reproductive hormonal profile. 

No harm to rethink how you can incorporate IF into your daily eating regimen and adjust your eating hours accordingly. Again, the goal is not to compromise the rest of the fertility nutrients needs while you’re on IF.

Watch The Fertility Nutrition TV – Which Is The Best Fertility Diet?

Finally…

Don’t aim to lose weight fast. 

You probably have been on a diet before, but each time you lost weight, you struggle to follow it through. Do you ever beat yourself up?

Failure is a natural part of one’s journey of losing weight. It doesn’t need to be the end of your story – unless that’s what you choose. 

If you’re struggling with weight and fertility, the secret is moving on from failure and take every chance you have to learn, eat better every day, grow stronger, and you’re more capable of achieving your ultimate dream as you thought.

All my love ❤️,

Catherine

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