The “One Meal a Day” (OMAD) diet has gained traction on social media as a seemingly simple solution for weight loss and better metabolic health. But what does OMAD actually do to your body, mind, and relationship with food, especially if you’re a woman?

As a dietitian who supports a mindful, sustainable approach to eating, I’ve seen OMAD promoted across my news feeds over the past few weeks. It promises big results, but what are the costs—and are those results supported by science?

In this article, we’ll unpack OMAD from both a scientific and mindful eating perspective. If you’ve been curious about trying it (or already have), this is a must-read.

What is OMAD?

OMAD is an extreme form of time-restricted eating. It involves consuming all of your daily calories within a one-hour eating window and fasting for the remaining 23 hours. It falls under the umbrella of intermittent fasting (IF).

OMAD has gained popularity for:

• Weight loss
• Simplicity
• Potential metabolic health benefits

According to Tinsley & La Bounty (2015) and Varady (2011), variations of intermittent fasting like OMAD show some short-term metabolic improvements. But as we’ll explore, the evidence isn’t as strong as social media might suggest.

The Promises of OMAD: Hope or Hype?

1. Simplicity

Many people are drawn to OMAD for its straightforward nature. Planning and preparing only one meal per day reduces decision fatigue and can feel freeing for those overwhelmed by food planning.

No foods are strictly off-limits, which may appeal to those tired of rigid diet rules.

2. Possible Improvements in Insulin Sensitivity & Inflammation

Some studies on time-restricted feeding (not OMAD specifically) show potential reductions in insulin and C-reactive protein levels. Fasting may also reduce LDL “bad” cholesterol.

However, these benefits are most often observed with early time-restricted feeding (e.g., eating between 7 a.m. and 3 p.m.), not the OMAD pattern. A 2023 systematic review found little evidence that intermittent fasting outperforms traditional calorie restriction for weight or metabolic improvements.

3. Weight Reduction

One of OMAD’s biggest claims is weight loss—but does it deliver?

While some people lose weight due to a lower calorie intake, evidence shows OMAD is not significantly more effective than other methods. The key factor in weight change remains energy balance, not meal timing alone.

4. Increased Awareness of Hunger

From a mindful eating perspective, fasting for longer periods might help you become more aware of true hunger cues. But this only works if those cues are honoured in a timely and gentle way.

Ignoring hunger or suppressing it repeatedly can lead to disconnection from your body’s natural signals, setting the stage for overeating, fatigue, or emotional distress.

The Risks of OMAD

1. Overriding Natural Hunger and Satiety Signals

Going 23 hours without food can disconnect you from hunger and fullness cues. Many people find themselves bingeing or feeling overly full after breaking their fast.

This pattern can lead to a cycle of extreme hunger followed by overeating—the opposite of mindful nourishment.

Studies show that OMAD may increase fasting blood sugar, delay insulin response, and raise levels of the hunger hormone ghrelin compared to eating multiple meals a day.

Mindful Eating Insight: Mindful eating is guided by internal cues—not the clock. Eating in harmony with your hunger promotes balance and trust.

2. Nutritional Deficiencies

It’s difficult to meet your macro- and micronutrient needs in one meal.

Risks include deficiencies in:

• Fiber
• Protein
• Iron
• Calcium
• B vitamins

Stote et al. (2007) found that participants following OMAD had higher blood pressure and hunger levels compared to those eating three meals a day, despite weight loss. Nutrient intake was also significantly reduced.

3. Mental Health and Focus

Fasting for extended periods can increase irritability, anxiety, and fatigue. Women, in particular, are more vulnerable to the emotional and cognitive effects of food restriction.

Long fasts can also lead to obsessive thoughts about food and increase the risk of disordered eating patterns, such as binge eating or orthorexia (an unhealthy fixation on “clean eating”).

Study Highlight: Trepanowski et al. (2017) found that alternate-day fasting was not more effective than daily caloric restriction, but participants reported greater mood swings and food preoccupation.

4. Hormonal and Metabolic Concerns for Women

Women’s hormonal systems are finely tuned and deeply connected to eating patterns. Here’s how OMAD and other forms of intermittent fasting can affect women differently at various life stages:

Premenopausal Women (<40 years old)

Energy restriction can reduce progesterone levels, especially in the second half of the menstrual cycle. This can disrupt ovulation and cause irregular periods.

Fasting can also increase cortisol (a stress hormone), which then disrupts insulin, estrogen, and progesterone levels.

Tip: Avoid long fasts during days 21–28 of your cycle. A 12-hour overnight fast is often safer.

Perimenopausal Women (40s to early 50s)

Hormones are shifting, and the body becomes more sensitive to stress. Extreme intermittent fasting may exacerbate symptoms like hot flushes, fatigue, and mood swings.

Guidance from a health professional is highly recommended before trying OMAD at this stage.

Postmenopausal Women

Hormonal levels are more stable, so mild intermittent fasting (like a 12-hour overnight fast) may be better tolerated. Some women may see benefits in insulin sensitivity and body composition.

Still, a mindful, personalised approach is best. Monitor how your body responds and consult a health practitioner.

Thyroid and Fertility

Prolonged fasting may suppress thyroid function, affecting energy, mood, and fertility. Reduced thyroid hormone production has been linked to lower progesterone and ovulatory issues.

5. Other Negative Health Consequences

Research from a large U.S. study of over 24,000 adults found that:

• Eating only one meal per day increased the risk of all-cause mortality
• Skipping breakfast raised cardiovascular mortality risk
• Skipping lunch or dinner raised general mortality risk

Additionally, OMAD may:

• Increase the risk of type 2 diabetes
• Impair glucose control
• Contribute to lean muscle loss
• Reduce bone density

Mindful Eating Insight: Health isn’t about eating “less”—it’s about eating with care, variety, and nourishment. Diets like OMAD often fall short on all three.

A Mindful Eating Perspective: What Really Works?

The mindfulness approach encourages you to ask:

• Am I eating in a way that supports my energy, emotions, and hunger?
• Do I feel peaceful or anxious around food timing?
• Am I truly satisfied, physically and emotionally, after eating?

Rather than restricting eating to a narrow window, mindful eating supports tuning into hunger and fullness cues and making compassionate food choices based on what your body needs.

It also takes into account life stages, medical conditions, and emotional well-being.

Mindful Eating Principle: Honour your body’s signals, not a set of external rules.

So, Should You Try OMAD?

Let’s be clear: there’s no single way of eating that works for everyone.

But OMAD raises several red flags, particularly for women:

• It can disrupt hormones
• It increases risk of nutritional deficiency
• It may negatively affect mood, focus, and energy
• It poses long-term health risks without guaranteed benefits

If you’re curious about improving your eating habits, mindful eating offers a flexible, evidence-informed, and compassionate way forward.

Key Takeaways

1. OMAD disconnects people from their hunger cues and may increase risk of overeating.
2. Scientific evidence shows no long-term advantage of OMAD over balanced eating.
3. Hormonal health—including thyroid, menstrual, and fertility health—can be negatively impacted.
4. Emotional effects include fatigue, anxiety, and obsessive thoughts about food.

5. Mindful eating supports lasting health by tuning into what your body truly needs.

Need Support Reconnecting with Your Body?

If you’ve tried dieting, fasting, or OMAD and feel confused or stuck, you’re not alone.

There is a better way.

Join me for a complimentary Mindful Eating Discovery Call where we explore what truly supports your body, mind, and long-term health—without restriction, guilt, or shame.

Or explore the Foundations Mindful Eating Program, where women just like you are learning to rebuild trust with food, balance hormones, and reclaim energy.

Because your health deserves more than a trend.

References

• Sutton et al., 2018, Cell Metabolism
• Stote et al., 2007, AJCN
• Trepanowski et al., 2017, JAMA Internal Medicine
• Tinsley & La Bounty, 2015, Journal of the International Society of Sports Nutrition
• Varady KA, 2011, Obesity Reviews