More than 21 million American adults work the night shift. While we sleep, they move vital goods, keep watch over our safety, and provide essential labor as emergency responders racing through darkened streets, nurses tending sick patients, and pilots navigating by instrument.
Night workers provide another important service: They provide real-world data about sleep and diet habits that help researchers assess the health risks facing anyone who gets disrupted sleep.
These risks include desynchronized circadian rhythms, increased fatigue, unhealthy eating, and chronic disease.
“Shift workers have a greater risk of developing cardiometabolic diseases, such as overweight and obesity, type 2 diabetes, cardiovascular disease, and metabolic syndrome,” said Maxine Bonham, PhD, a registered nutritionist and professor of nutrition, dietetics and food at Monash University in Melbourne, Australia, at a 2025 sleep conference in Singapore.
“All of these disorders have been associated with sleep deprivation, disordered sleep, and with nutrition-related disorders,” Bonham said.
Here’s what night workers have taught us.
We Tend to Eat More Calories at Night
Graveyard shift employees end up eating a little more than daytime workers do in 24 hours, Bonham said. Over time, that little extra adds up.
“What you've got to think about is the types of foods that shift workers eat,” Bonham said. They tend to have more total and saturated fats and less fiber, for example.
In a study of firefighters in Melbourne, those working the night shift ate less fruit and more “discretionary” foods — extra, lower-nutrient foods and drinks that are not necessary for health and typically eaten for enjoyment.
And it’s not just how much night shift workers eat, but when. Eating a majority of your daily calories at night has been shown to slow metabolism and promote fat storage, which helps explain why late-night eating is linked to weight gain.
Night Workers Gain More Weight Than Day Workers
A study comparing 36 daytime nurses, nurse aides, and hospital security staff with 49 night-shift workers found that those working late shifts gained an average of 4.3 kilograms (nearly 10 pounds) after starting night work. In contrast, daytime workers gained an average of 0.9 kilograms (about 2 pounds).
In the Australian firefighter study, some first responders said they eat when they are not hungry in case they get called to an emergency. In other cases, they eat just because they’re bored. “It's something to do to stay awake,” Bonham said.
The Home-Cooked Advantage
Some night shift workers do not have facilities at work for storing and heating up food from home. That means they tend to eat restaurant food, including takeout, overnight. In general, they’re missing out on what nutritionists call the “home-cooked advantage.”
Restaurant food tends to be higher in saturated fat, salt, and calories — and lower in healthy nutrients — than are foods prepared at home.
In a 2023 study, paramedics working the night shift added 5 centimeters (almost 2 inches) to their waist size, on average, and crossed the BMI threshold from normal weight to overweight over two years. “So imagine 10 years or 15 years of night shift work and the impact on metabolic health,” Bonham said.
Potential Solutions
If you are continually sleep deprived or among the legion of night shift workers, one potential strategy is intermittent fasting, an eating pattern that includes periods of voluntary fasting.
In a 2025 study, Bonham and colleagues compared 250 graveyard shift workers — some who ate intermittently (fasting for two days per week) and others who cut calories.
After 24 weeks, the “cut calories” group lost a mean of 5.3 kilograms (more than 11 pounds), similar to the fasting night workers, who lost a mean of 5.2 kilograms. The greatest weight loss was among those who fasted during night shifts (as opposed to days off); they lost a mean of 7.9 kilograms (more than 17 pounds).
Bonham said she and colleagues were happy with the results. “We saw what we expected,” she said, “which was a reduction in weight and a reduction in the number of cardiometabolic markers.”
