Time-restricted eating has become increasingly trendy, but a new study reveals that while intermittent fasting can aid in weight loss, it may not deliver on broader health promises.

In a concise study conducted in Germany, researchers observed that participants following two different time-restricted eating plans lost weight but showed no improvement in crucial health indicators such as blood glucose, blood pressure, and cholesterol levels.

The study involved 31 women who were either overweight or obese. One group adhered to an eating window from 8 a.m. to 4 p.m., while the other group ate between 1 p.m. and 9 p.m. over a two-week period, all while consuming their usual amount of calories, as detailed in a press release.

Published in the journal Science Translational Medicine, the study suggests that any touted cardiometabolic advantages of intermittent fasting may be due to reduced calorie intake rather than the timing of meals, according to the researchers.

Additionally, the study noted changes in the participants’ circadian rhythms, or sleep/wake cycles, while on the time-restricted schedules, though the health consequences of these shifts remain unclear.

The study did have some limitations. Some researchers have cast doubt on the significance of the study due to its small size.

“It is severely underpowered to detect any difference, considering how gentle the intervention is,” Dr. Dr. Jason Fung, a Canadian physician, author and researcher, told Fox News Digital. He also noted that the participants were fasting for 16 hours a day instead of the normal 12 to 14 hours.

Lauren Harris-Pincus, a registered dietitian nutritionist in New Jersey, agreed that the findings could be due to the fact that there was no intentional caloric restriction, and reiterated that the sample size is “quite small.” 

“As a registered dietitian, I only recommend time-restricted eating when it is carefully planned and shifted earlier within the day,” Harris-Pincus, who was not involved in the study, told Fox News Digital.

“Only one in 10 Americans consumes the recommended number of fruits and veggies, and 93% miss the mark on fiber goals. Restricting an eating window necessitates more careful meal planning to ensure adequate intake of macro- and micronutrients.”

The expert also cautioned that skipping breakfast to enable a later eating window may result in lower intake of the “nutrients of concern” in the American diet, including calcium, potassium, fiber and vitamin D. 

Looking ahead, the researchers said more studies are needed to explore the effects of time-restricted eating over longer time periods. It also remains to be seen how the combination of caloric restriction and time-restricted eating may affect outcomes.

Future research could also explore how different populations may respond.

Dr. Daryl Gioffre, a gut health specialist and celebrity nutritionist in New York, noted that the study didn’t account for critical factors like chronic stress, sleep quality, medications, hormone status and baseline metabolic health.

“All of these can significantly blunt fat loss and cardiometabolic improvements,” Gioffre, who also was not involved in the research, told Fox News Digital.

“Cortisol, the body’s primary stress hormone, is naturally highest in the morning, which overlaps with one of the fasting windows studied,” he went on. “If stress is elevated, cortisol alone can block fat burning, disrupt blood sugar regulation, and mask cardiovascular improvements, regardless of calorie intake or eating window.”

Gioffre did agree, however, that growing research shows intermittent fasting — when done correctly and sustained over time — can improve insulin regulation, reduce inflammation, support fat loss and contribute to better cardiovascular health.

“These are outcomes that simply cannot be captured in a short, stress-blind study like this,” he added.

Fox News Digital reached out to the researchers for comment.