Can OMAD improve fertility by reducing weight or insulin resistance?

For some overweight individuals with PCOS, short-term intermittent fasting (like 14:10) may improve ovulation. But OMAD is too extreme for most women and may do more harm than good.

Will OMAD affect ovulation?

Yes, OMAD can suppress ovulation by reducing energy availability and disrupting the hormonal signals needed for egg release.

Can I do OMAD during IVF or egg freezing?

No. During IVF, you need consistent nutrient intake to support egg maturation, hormone production, and uterine lining development. OMAD is not recommended.

How do I know if OMAD is hurting my fertility?

Warning signs include missed periods, extreme fatigue, hair thinning, low libido, or feeling cold often. If you experience any of these, stop OMAD and consult a gynaecologist or reproductive endocrinologist.

How OMAD Affects Hormones and Fertility in Women

Your reproductive system depends on regular energy availability. When you drastically reduce your eating window or calorie intake, especially through OMAD, your body can shift into a metabolic state where reproduction is deprioritised in favour of survival.

Here’s how OMAD can influence key hormones involved in fertility:

GnRH (Gonadotropin-Releasing Hormone): OMAD may reduce the frequency of GnRH pulses, which impacts ovulation. This can disrupt the menstrual cycle or lead to anovulation.
LH & FSH (Luteinising and Follicle-Stimulating Hormones): These hormones can become suppressed under low energy availability, reducing the chance of ovulation and impacting follicle development.
Leptin: Leptin, which signals that the body has enough energy to support reproduction, often drops with extreme calorie restriction. Low leptin levels are associated with amenorrhea and infertility.
Insulin and Glucose: OMAD can improve insulin sensitivity in some people, but extreme fasting can also increase cortisol, which in turn impairs insulin control in others, especially those with PCOS or adrenal sensitivity.

Who Should Be Cautious with OMAD?

OMAD is particularly risky for reproductive health in certain groups:

Women with irregular periods or hypothalamic amenorrhea
Women underweight or with low body fat
Athletes or those engaging in intense exercise
Anyone undergoing IVF or egg freezing
Women with PCOS who experience adrenal-type symptoms

Possible Effects on Fertility and Menstrual Cycles

Depending on how OMAD is practiced, these are the effects seen in women:

Menstrual Irregularities

Many women report missed periods or changes in cycle length after starting OMAD.
In some cases, periods stop altogether due to calorie or nutrient deficiency.

Reduced Egg Quality or Ovulation Issues

Poor nutrition or energy deficiency can impair follicular development and egg maturation.
Animal studies suggest that severe caloric restriction can shrink ovarian size and reduce ovarian reserve markers.

Hormonal Dysregulation

Fasting longer than 16 hours can increase cortisol and suppress reproductive hormones.
Long-term suppression of estrogen and progesterone can impact endometrial thickness, which is crucial for implantation.

What About OMAD for PCOS?

For some women with insulin-resistant PCOS, intermittent fasting might temporarily help regulate cycles and reduce inflammation. But OMAD can quickly become counterproductive:

Excess cortisol from prolonged fasting may worsen adrenal-type PCOS symptoms.
Fasting can suppress thyroid function, leading to fatigue and worsened metabolic markers in the long run.

A 14–16 hour fast with two nutrient-dense meals may be safer than OMAD for most people with PCOS.

Why OMAD Might Be Riskier for Women in India

In India, nutrient deficiencies (especially in iron, B12, D, and zinc) are more common, especially among vegetarians or those from lower socioeconomic backgrounds. With OMAD, it becomes extremely difficult to meet these nutrient needs in just one meal:

Iron deficiency anaemia is already a top cause of ovulatory issues in Indian women.
Vitamin D deficiency, widespread across the country, plays a role in hormone regulation and egg health.
Protein intake is often too low to support muscle and reproductive hormone synthesis.

Better Alternatives: Time-Restricted Eating That Supports Fertility

If you're looking to balance metabolic health with fertility, a more moderate approach works better:

12:12 or 14:10 fasting (eat within a 10- to 12-hour window) helps regulate insulin without extreme restriction.
Cycle-syncing meals: Slightly larger breakfasts during the follicular phase and protein-rich meals during the luteal phase can support hormonal rhythms.
Mediterranean or Ayurvedic-inspired eating patterns that emphasise warmth, satiety, and regular mealtimes work better for supporting reproductive health.

OMAD and IVF or Fertility Treatments: A No-Go

Most fertility specialists discourage extreme diets around IVF because:

The egg maturation phase (especially during stimulation) requires ample calories, antioxidants, and protein.
Even mild under-eating can affect endometrial thickness and implantation chances.
The gut microbiome and hormone regulation both require consistent, balanced nutrient intake, not starvation patterns.

For women, fertility isn’t just about having enough eggs. It’s about whether the body feels safe and nourished enough to prioritise reproduction. OMAD, despite its metabolic appeal, often sends the opposite signal. When energy availability dips too low, your brain pulls the brakes on ovulation, hormone production, and endometrial readiness. Whether you're trying to conceive, preserving fertility, or simply regulating your cycle, one meal a day may do more harm than good. In most cases, sustainable hormonal balance demands nourishment, not deprivation. Listen to your body. Reproductive health thrives on rhythm, not extremes.

FAQs on What Happens to Your Hormones When You Eat Just Once a Day?

Can OMAD improve fertility by reducing weight or insulin resistance?
For some overweight individuals with PCOS, short-term intermittent fasting (like 14:10) may improve ovulation. But OMAD is too extreme for most women and may do more harm than good.
Will OMAD affect ovulation?
Yes, OMAD can suppress ovulation by reducing energy availability and disrupting the hormonal signals needed for egg release.
Can I do OMAD during IVF or egg freezing?
No. During IVF, you need consistent nutrient intake to support egg maturation, hormone production, and uterine lining development. OMAD is not recommended.
How do I know if OMAD is hurting my fertility?
Warning signs include missed periods, extreme fatigue, hair thinning, low libido, or feeling cold often. If you experience any of these, stop OMAD and consult a gynaecologist or reproductive endocrinologist.