What is functional hypothalamic amenorrhea (HA)?
Author: Cynthia Donovan, MS RDN CDN
Functional hypothalamic amenorrhea is a form of secondary amenorrhea, meaning menstrual periods stop after they have previously occurred.
It develops when the hypothalamus reduces its signaling to the reproductive system. This can disrupt the hormonal signals needed for normal ovarian function, ovulation, and menstruation.
HA is commonly associated with low energy availability, restrictive eating patterns, excessive exercise, psychological stress, or a combination of these factors.
Importantly, HA is a diagnosis of exclusion. Other possible causes of a missing period, including pregnancy, thyroid disorders, hyperprolactinemia, polycystic ovary syndrome (PCOS), and primary ovarian insufficiency, need to be appropriately evaluated.
A missing period is not simply an inconvenience. It can reflect changes in reproductive hormones and have implications for bone health and other aspects of long-term health.
This is why understanding what may be contributing to your missing period matters.
What did the 2026 study on nutrition and HA find?
In the study, “Dietary Intake of Macronutrients and Micronutrients in Women with Functional Hypothalamic Amenorrhea,” researchers compared the dietary intake of 30 women with HA with that of 29 women who had regular menstrual cycles.
Participants completed a three-day food diary. The researchers analyzed their reported energy intake, macronutrients, and micronutrients from foods and beverages, excluding supplements from the nutrient calculations.
Here are the main findings.
1. Women with HA reported a similar calorie intake to women with regular periods
This is one of the most interesting findings.
The median daily calorie intake was approximately:
Women with HA: 1,739 calories per day.
Women with regular menstrual cycles: 1,732 calories per day.
The difference was not statistically significant.
The researchers also found no significant differences in body mass index, waist-to-hip ratio, or self-reported exercise patterns between the groups.
What does this mean?
It does not mean that 1,739 calories is enough for a woman with HA. It certainly does not mean that eating more cannot help restore her period.
Instead, it highlights an important limitation of looking at a calorie number in isolation.
A three-day food diary provides only a snapshot of reported intake. It cannot tell us with certainty whether an individual is meeting her energy needs over time, how accurately she reported her intake, or how her intake compares with her total physiological demands.
Energy needs differ between individuals, and the amount of food someone needs to support reproductive function depends on more than a single daily calorie estimate.
The takeaway: Similar reported calorie intake does not establish similar energy availability or prove that two women have the same nutritional needs.
2. Women with HA consumed more protein and dietary fiber
The researchers found that women with HA reported consuming more protein and fiber than the women with regular cycles.
NutrientWomen with HA Women with regular cycles Protein 84 g/day74 g/day Dietary fiber 30 g/day17 g/day Carbohydrates 205 g/day207 g/day Fat 63 g/day62 g/day
The differences in protein and fiber were statistically significant. The differences in carbohydrate and fat intake were not.
This is particularly interesting because protein and fiber are often emphasized in health-conscious eating patterns.
Protein is essential, and fiber supports digestive and metabolic health. Neither nutrient is inherently problematic, and this study does not establish that higher protein or fiber intake causes HA.
However, the findings raise an important question when considered alongside the researchers' discussion: could some women be prioritizing protein-rich, high-fiber, nutrient-dense foods while still not meeting their overall energy needs?
For example, someone might build meals around lean protein, vegetables, fruit, and other high-fiber foods while unintentionally limiting energy-dense foods, dietary fat, carbohydrates, or the overall amount she eats.
Another woman might eat plenty of protein but struggle to eat consistently throughout the day or provide enough energy to support her exercise routine and reproductive function.
These are possibilities to explore in an individual assessment, not conclusions we can draw about every participant in the study.
The point is not to avoid protein or fiber. It is to make sure that a focus on food quality does not come at the expense of adequate overall nourishment.
3. Some micronutrient intakes were higher, while vitamin D intake was low
The study also examined vitamins and minerals from food.
Women with HA reported higher dietary intakes of vitamin A, vitamin C, and iron relative to the estimated average requirements used in the study.
The differences in vitamin A, vitamin C, and iron were statistically significant. Vitamin D and calcium intake did not differ significantly between groups.
The vitamin D findings deserve attention. Both groups reported dietary vitamin D intake well below the estimated average requirement used in the analysis.
However, dietary intake is not the same as vitamin D status. The researchers did not establish vitamin D deficiency through these food diary findings, and supplement intake was excluded from the nutrient calculations.
The higher vitamin A intake also requires careful interpretation. The study measured vitamin A from food but did not establish that participants had excessive vitamin A levels or that their intake caused harm.
The authors discussed potential implications for bone health, particularly given the effects of low estrogen on bone. They also emphasized the need for further research.
For women with HA, these findings reinforce the value of looking at the whole nutritional picture rather than assuming that a diet rich in vitamins and minerals necessarily meets every physiological need.
Eating a variety of nutritious foods matters. So does consuming enough overall energy and considering the nutrients that may be lacking.
4. Body size and exercise habits did not explain everything
The women with HA and the control group had similar average BMI and similar self-reported physical activity patterns.
The median reported duration of moderate-to-vigorous activity was five hours per week in the HA group and four hours per week in the control group. This difference was not statistically significant.
That finding matters because women can develop HA without being underweight, and a person's body size alone cannot establish whether she is adequately nourished.
Likewise, a general description of exercise frequency does not tell us everything about an individual's training load, recovery, energy expenditure, or response to stress.
Two women may have similar body sizes and report similar exercise habits but have very different nutritional needs and hormonal responses.
This does not mean that exercise or body weight is irrelevant. It means that neither should be interpreted in isolation.
Why HA recovery is about more than “eat more and rest more”
If you have HA, I want you to understand something important: eating more and reducing excessive exercise can be essential, but recovery is not always as simple as following a universal set of instructions.
This study supports a more nuanced conversation about nutrition. It does not prove that calories are unimportant, nor does it establish that micronutrient imbalances cause HA.
Instead, it shows that the dietary patterns of women with HA may differ in ways that are not captured by total calorie intake alone.
In practice, there are several areas worth exploring.
Your total energy intake and energy availability
Are you consistently eating enough to meet your body's needs, including the demands of daily living, exercise, recovery, and reproductive function?
A food diary or calorie estimate can provide useful information, but it is only one part of the assessment.
Your meal timing, portion sizes, food variety, training schedule, and ability to eat enough consistently throughout the day may all be relevant.
Your overall macronutrient balance
Are you eating enough carbohydrates, fats, and protein in the context of your individual needs?
The goal is not to find a perfect macronutrient ratio or label one nutrient as the problem. It is to ensure that your eating pattern provides sufficient energy and a balanced range of nutrients.
For some women, that may involve adding more substantial meals, increasing snacks, incorporating more energy-dense foods, or moving away from rigid rules around carbohydrates and fats.
For others, the priority may be consistency, flexibility, or addressing fears that make eating enough difficult.
Your micronutrient intake and bone health
A varied diet is important, but nutritional adequacy cannot be established by looking at food quality alone.
Depending on your history, symptoms, diet, and clinical findings, a registered dietitian and healthcare professional may assess particular nutrient intakes and determine whether further evaluation is appropriate.
This is especially relevant in HA because prolonged low estrogen can affect bone health.
Supplements are not a substitute for adequate energy intake, and more is not automatically better. Supplementation should be individualized rather than based solely on the findings of this small study.
Your relationship with food, exercise, and body changes
The researchers discuss psychological characteristics that can occur in women with HA, including perfectionism, fear of weight gain, and restrictive eating behaviors.
These patterns can make recovery difficult even when someone understands what she needs to do.
You might know that eating more is important but struggle to add food because you fear your body changing. You might reduce your workouts but feel anxious when you are less active. You might choose foods based on what seems healthiest while finding it difficult to eat enough of them.
These experiences deserve attention alongside your nutritional needs.
They are not evidence that you lack willpower, and they are not issues that can always be resolved by handing someone a meal plan.
Support may involve nutrition counseling, medical evaluation, and psychological care when appropriate.
Your individual hormonal and medical picture
HA should not be diagnosed from a food diary alone.
A comprehensive evaluation considers menstrual history, symptoms, hormone testing when appropriate, and other potential causes of amenorrhea.
If your period has been absent for three months or longer, arrange an evaluation with a qualified healthcare professional rather than assuming that nutrition or stress is the only explanation.
Understanding the broader picture helps guide appropriate care and prevents other causes from being overlooked.
What are the limitations of this HA nutrition study?
Although the findings are useful, there are several reasons to interpret them carefully.
First, the study included only 59 women, with 30 in the HA group and 29 controls. A larger study would help determine whether these findings apply more broadly.
Second, the researchers used three-day food diaries. These are useful for examining reported intake but can be affected by underreporting, recall, and changes in eating behavior while recording food.
Third, the study was cross-sectional. It compared women at one point in time and cannot establish whether particular dietary patterns caused HA or resulted from the behaviors and circumstances associated with it.
Fourth, the nutritional analysis excluded supplements. This is particularly relevant to vitamin D and other nutrients for which supplement use may contribute substantially to total intake.
Finally, the study did not test a period-recovery intervention. It cannot tell us which dietary changes will restore menstruation in an individual woman or whether changing a specific macronutrient or micronutrient will improve recovery.
The findings are best understood as a reason to investigate nutrition in greater depth, not as a new set of rules for women with missing periods.
What I want women with HA to take away from this research
If you have been trying to get your period back, I do not want you to read this study and conclude that you need to eliminate fiber, stop eating protein-rich foods, or follow a completely different diet.
That is not what the evidence says.
I want you to recognize that a missing period deserves a more thoughtful approach than simply comparing your calorie intake with someone else's.
You can eat nutritious foods and still not eat enough overall. You can have a BMI within the expected range and still experience HA. You can understand the importance of recovery and still need help identifying the patterns, nutritional needs, and barriers that are relevant to you.
And you do not have to figure all of this out on your own.
In my work as a registered dietitian, I look beyond a single calorie target or a generic instruction to eat more. Individualized period recovery support considers your food intake, eating patterns, movement, recovery, medical history, and the challenges that may make changes difficult to sustain.
The goal is not to create a more complicated set of food rules. It is to understand what your body needs and help you move toward recovery in a way that supports your health beyond the return of your period.
Ready to make eating for period recovery feel less overwhelming?
If you are struggling to figure out what to eat, how to build more satisfying meals, or how to nourish your body consistently while working toward getting your period back, start with my free meal guide.
It is a practical resource to help you think about meals and nourishment without having to reinvent everything you eat each day.
Get your free period recovery meal guide here.
You deserve support that looks at the whole picture, not just a number on a food tracker.
Research reference
Uddenberg ER, Safwan N, Castaneda R, et al. Dietary Intake of Macronutrients and Micronutrients in Women with Functional Hypothalamic Amenorrhea. Journal of Women's Health. 2026. doi:10.1177/15409996261428013.
