A new study has revealed that dieting purely for health or cosmetic appearance can inadvertently lead to severe sleep deprivation, with women experiencing significantly harsher impacts than men.
A research team led by Professor Park Min-seon of the Department of Family Medicine at Seoul National University Hospital analyzed data from 10,299 adults who participated in the 2019–2022 Korea National Health and Nutrition Examination Survey. Their findings, published in a recent issue of the Korean Journal of Family Medicine, demonstrated that women whose daily energy intake fell far short of their actual energy expenditure faced a substantially higher risk of insufficient sleep.
Striking an Energy Balance Minimizes Sleep Risks
To evaluate this relationship, the research team calculated an estimated energy balance index by subtracting the calories burned through an individual's basal metabolic rate and physical activity from their total daily caloric intake. A negative value represented an energy-deficient state, while a positive value denoted an energy surplus. Based on these calculations, the participants were divided into four quartiles to assess their risk of short sleep, defined as securing less than six hours of sleep per day.
The core finding centered heavily on biological equilibrium. Among female participants, the group in a severe caloric deficit exhibited the highest risk of short sleep. In contrast, the "energy balance" group—those whose caloric intake closely matched their physical expenditure—boasted a 29% lower risk of sleep deprivation compared to the deficit group. Interestingly, the groups maintaining a slight energy surplus (third quartile) or an explicit excess (fourth quartile) also saw reduced risks of short sleep, dropping by 25% and 24% respectively.
Notably, the protective benefits to sleep were more pronounced in the group that achieved an appropriate caloric balance than in the group that simply consumed the most energy. This underlines that optimizing sleep quality is not a matter of overeating, but rather of cultivating dietary habits that adequately replenish the exact amount of energy the body expends.
Why Severe Caloric Deficits Selectively Disrupt Women's Sleep
Intriguingly, this clear correlation between energy imbalance and sleep deprivation did not manifest in male participants. The research team attributed this divergence to distinct sex differences in neuroendocrine-immune regulation. During sleep, the human body actively reorganizes the immune system, a process that expends approximately 400 kcal of energy. When the body suffers from a severe energy deficit, it activates the hypothalamic-pituitary-adrenal (HPA) stress axis, releasing hormones that directly interfere with deep, restorative sleep.
Women are believed to be significantly more sensitive than men to fluctuations in regulatory biomarkers such as cortisol, leptin (the appetite-regulating hormone), and estrogen. Consequently, a steep caloric deficit triggers a sharper decline in female sleep architecture.
"This study confirms that aggressive dieting—whether by drastically cutting food intake or solely increasing exercise—can severely undermine sleep health," emphasized Professor Park Min-seon. "For women, maintaining a strict balance by eating appropriately in accordance with physical activity levels is a foundational prerequisite for good sleep. Protecting public health requires personalized wellness strategies, with distinct energy-balance targets tailored to sex, occupation, and lifestyle characteristics."
