Infuse Infuse 1 September 2017 | Page 37

Overall, the research shows that lower-carbohydrate diets have a more positive impact on
reproductive hormones, ovulation rates and pregnancy rates than standard diets in women who are
overweight or obese. However, before adopting a low-carbohydrate diet, there are a few important
factors to keep in mind:
1. The research does not yet confirm how
low in carbohydrates the diet should be.
Our research was based on diets which were less than
45% carbohydrates, so that we could include Very Low
Energy Diet studies (also known as intensive phase
meal replacements, where all meals are replaced with
meal replacements). However, although lower than
usual, 45% carbohydrates is not ketogenic for many
people.
2. There’s one small prospective study
which used meal replacements (which
didn’t meet the criteria for inclusion into
our systematic review), and actually
reduced the number of eggs available for
fertilisation iv !
This provides a caution that low-carbohydrate
diets may not be suitable for everyone wanting to
optimise their fertility. One possible alternative may
be a low-carbohydrate diet for short-term weight
loss, followed b y a period of slight weight regain.
This practice, known as “flushing”, is often used to
improve the fertility of farm animals v . A pattern of
a period of weight loss, followed by a period of
weight regain, has also been found to demonstrate
a positive impact on reproduction in women.
Consequently, I believe that a low-carbohydrate diet
should only be utilised for a short period of time to
optimise menstrual cyclicity and fertility hormones,
followed by a period of renourishment.
3. Optimal nutrition
is essential in the
lead-up to pregnancy.
Wholegrains are some
of the best sources of
key fertility nutrients,
such as iodine and
folate.
Women following a low-
carbohydrate diet without
meeting all their nutritional
requirements could do
more harm than good,
so it’s essential to ensure
that our clients are indeed
meeting these nutritional
requirements.
LEARN MORE:
• To see the review, or for further
information, go to www.
melaniemcgrice.com.au/research.
• Follow Melanie on Facebook for
regular updates about nutrition
for fertility, pregnancy and
women’s health.
Connect with Melanie on LinkedIn
http://www.health.gov.au/internet/publications/publishing.nsf/Content/womens-health-policy-toc~womens-
health-policy-experiences~womens-health-policy-experiences-reproductive~womens-health-policy
experiences-reproductive-maternal~womens-health-policy-experiences-reproductive-maternal-fert
ii
Sim, K.A.; Partridge, S.R.; Sainsbury, A. Does weight loss in overweight or obese women improve fertility
treatment outcomes? A systematic review. Obes. Rev. 2014, 15, 839–850.
iii
http://ajcn.nutrition.org/content/90/1/23.short
iv
Tsagareli, V.; Noakes, M.; Norman, R.J. Effect of a very-low-calorie diet on in vitro fertilization outcomes. Fertil.
Steril. 2006, 86, 227–229.
v
Butler, S.T. Nutritional management to optimize fertility of dairy cows in pasture-based systems. Animal 2014,
8, 15–26.
i
© Dietitian Connection
37
Infuse | September 2017