A recent study recommended that there can be optimal times of day for fasting and eating. The optimal time for metabolism is mid-to-late morning. The internal biological clock makes better at performing distinct things at diverse times of the day. When compared to eating the same meals earlier in the day, eating later in the day made participants feel more hungry throughout the course of a 24-hour period, according to the findings of a study. Furthermore, eating late led to fat tissue that retained more calories and burnt calories at a slow pace. Together, the alterations might make obesity more likely.

Investigators found in another study that among firefighters doing shift work, the intake of meals within a 10-hour window lowered the bad cholesterol particle size, that might reduce risk factors for heart disease. In individuals suffering from health concerns including high cholesterol, high blood pressure, and diabetes, the 10-hour eating window also led to improvements in blood sugar levels and blood pressure.

The findings of the two novel studies supported those of earlier investigations that suggested that people might have an ideal eating window on the basis of circadian rhythms, that control sleep and waking cycles and affect levels of sugar in blood, metabolism, and hunger. For example, the 10-hour window seemed to be a "sweet spot" for the body in firefighter research. Implementation of more rigorous limits, like those seen in many intermittent fasting regimens, might be hard for the body to sustain.

Despite having small sample sizes, the new studies provided information for future studies. In the 1st  trial, two 24-hour feeding regimens were evaluated on 16 obese or overweight subjects. Few of them commenced eating 1 hour following their normal wake-up time, while others didn't commence until over 5 hours later. For both groups, the nutrients and calories in their meals were similar.

When the hormones' levels were examined by the researchers, Leptin (hormone that results in feeling of fullness) was noted to be lower after consuming later. In addition, eating later doubled the possibility that individuals would experience persistent hunger. Volunteers in the research who ate later in the day also stated increased desires for meat and dairy, that are meals high in energy, along with starchy or salty items.

The study team also noted that alterations in fat tissue may raise the chance of making novel fat cells and decrease the chance of fat burning. Compared to early eaters, approximately 60 fewer calories were burnt throughout the day by late eaters. The body handles calories differently, due to eating late in the day. It tipped the scale in favor of gaining weight and body fat. According to this study, breakfast shouldn't be skipped.

The 2nd research tracked 137 firemen who had a Mediterranean diet comprising of olive oil, vegetables, fish, and fruits for twelve weeks. Seventy of them ate throughout a 10-hour window, while the remaining subjects ate over a larger window, approximately thirteen hours. Gadgets were utilized to monitor blood sugar levels and record meals on an app. Restricted window seems to permit the body to breakdown toxins and eradicate sodium and other things that can drive up blood sugar and blood pressure. Majority of the firemen in the 10-hour arm ate between 8 or 9 a.m. or 9 a.m. and 6 p.m. or 7 p.m.

In firefighters having risk factors for heart disease, like raised blood pressure and elevated blood sugar, time-restricted eating minimized their levels of blood pressure and blood sugar. Time-restricted eating appeared to be related to health benefits like minimized heart disease risk and reduction of dangerous cholesterol accumulation. Organs take a break from processing food during times of fasting, allowing them to focus their energy on healing cells instead.