If you are a regular reader of our blog, you know we are always paying attention to dieting trends. We want to know the current science and what folks are doing. Some fad diets are easy to write off as unhealthy. And, while some are unhealthy, they can come in and out of fashion again and again. But some diets are interesting because we’re still learning so much about them.
In April, we wrote a blog about how intermittent fasting might help blood sugar even if people didn’t lose weight. The extreme study allowed people to eat only four hours a day, three days a week. It wouldn’t be maintainable for most people.
A new study took a less extreme approach. Researchers had two groups of people who had borderline blood sugar concerns either eat 80 percent of their daily calories before 1 p.m. or eat 50 percent of their calories after 4 p.m. After one week, the two groups swapped eating habits. Everyone ate the same amount of calories, regardless of their group.
The participants had glucose tolerance tests before the study, on day seven and day 14. They wore continuous glucose monitors for the duration of the study. People who ate early in the day had fewer spikes.
“Eating the majority of one’s calories earlier in the day reduces the time that the blood sugar is elevated, thereby improving metabolic health,” said Dr. Joanne Bruno, a study author and endocrinology fellow at NYU Langone Health.
Dr. Pouya Shafipour, a family and obesity medicine physician at Providence Saint John’s Health Center, wasn’t surprised by the findings. “Studies show prolonged fasting and time restricted eating does help with insulin sensitivity and stabilizing blood sugar levels. So it puts the body in or extends the level of ketosis that we get into late at night. So the ketosis, in a sense, stabilizes blood sugar control more, and it prevents highs and lows, the peaks and valleys of blood sugar.”
The study was small, with only 10 subjects. It was well controlled. Ensuring that the number of calories was high enough to ensure no one lost weight meant that the results weren’t skewed by other factors. However, while it was well controlled, drawing universal conclusions from such a small group is unwise. A group of just 10 people isn’t reflective of a larger population. These results might not be the same if a larger group tried it.
Intermittent fasting is a less dangerous eating style than many other fad diets. This research offers more evidence that it can help some people with their blood sugar. However, we always recommend speaking to your doctor before making any changes to your routine. Large changes might not be suitable for you. And it’s essential to make sure that you are making healthy food choices, regardless of what time of day you’re eating!