The study found that intermittent fasting didn’t improve cholesterol levels, but it did significantly improve markers for insulin resistance and metabolic syndrome.
It’s a contentious topic: What makes up a healthy diet?
Researchers at the Intermountain Heart Institute decided to ask another question:
Could it be a matter of how often we eat rather than how much?
Their study, published in European Heart Journal Open, followed 67 participants for 6 months. Each participant had at least one symptom of metabolic syndrome, such as obesity, or they had type 2 diabetes.
None were taking diabetes or statin medications. All had elevated LDL (bad) cholesterol levels.
The small study found that fasting for 24-hour periods reduced insulin resistance and metabolic syndrome scores in the study participants.
Improved indicators of metabolic health
Study participants were between 21 and 70 years old. They were instructed to fast twice per week for 24 hours at a time for the first 4 weeks of the study, and then only once per week for the next 22 weeks.
A control group was allowed to eat whenever and whatever they wanted for the study period.
The findings suggest that intermittent fasting (IF) as it was practiced in this study didn’t improve cholesterol levels, but it did significantly improve markers for insulin resistance and metabolic syndrome.
Researchers also found that the fasting group had increased levels of a substance called galectin-3.
Ryan Barry, DO, a cardiologist at Staten Island University Hospital in New York, told Healthline that it’s a key protein for the body that plays a part in many cellular processes.
Benjamin Horne, PhD, principal investigator of the study, said galectin-3 is associated with inflammatory responses, and higher levels could mean reduced health risks.
“In finding higher levels of galectin-3 in patients who fasted, these results provide an interesting mechanism potentially involved in helping reduce the risk of heart failure and diabetes,” he said in a statement.
Inflammation and heart health
Understanding what causes inflammation in the body has long been a focus of medical experts.
According to Minisha Sood, MD, an endocrinologist at Lenox Hill Hospital in New York, reducing inflammation can improve the cardiovascular environment at a microscopic level.
“So when we think about cardiovascular risk, what are we really worried about?” Sood asked. “We’re worried about the microenvironment on the blood vessels, and is there an environment that is favoring the deposition of unfavorable cholesterol molecules and the recruitment of the immune system because of inflammation into those areas.”
Sood explained that this could build up plaque in blood vessels, which may eventually rupture, causing a cardiovascular event.
“So, getting at the root of what could potentially improve inflammation is critical,” she noted.
May reduce insulin resistance
Other recent researchTrusted Source also finds IF is not only effective at reducing body weight and blood sugar levels, but also at reducing insulin resistance.
“Insulin is essentially the ‘key’ to open the door to let glucose (sugar) into our cells, where glucose is used to produce energy,” Barry said.
When the body becomes resistant to insulin, glucose is unable to enter the cell and remains in the blood, he explained.
“The pancreas, which makes insulin, will try to make more insulin to get glucose out of the blood and into the cells,” Barry said. “Eventually, our pancreas can’t keep up the increased insulin production, and blood sugar levels continue to increase.”
Barry warned this could lead to inflammation and diabetes, conditions that affect many parts of the body and are associated with increased plaque buildup and risk of coronary artery disease.
Reducing the amount of time we eat is key
According to Sood, a 12- to 13-hour fast is what our bodies are designed to do so the liver can clean itself out.
“Looking at how many hours during the day is one consuming calories, if it’s more than 12 or 11 hours, that time frame needs to be shortened,” she said.
This isn’t intermittent fasting or even time-restricted eating. It’s a natural period of time, such as between dinner and breakfast, when people are not eating.
Sood also explained that eating healthier fats, fewer refined sugars, and very little, if any, processed foods — as well as allowing our bodies to rest, repair, and restore during the overnight hours — are ways besides IF to maintain a healthy metabolism and reduce disease risk.
“Fewer processed foods and lowered intake of refined sugars is also to keep the burden low on our body for making insulin,” Sood said.
Intermittent fasting versus time-restricted eating
Sood explained that IF shouldn’t be confused with time-restricted eating.
“Intermittent fasting is technically a fast of 24 hours or more,” she said. “And I just want to make the distinction between that and time-restricted feeding or time-restricted eating, which are fasts that are less than 24 hours.”
She confirmed that there are side effects associated with IF. They can include dizziness, low blood pressure, electrolyte abnormalities, and low blood sugar, especially if someone is on medication to lower their blood glucose or blood pressure.
“But for time-restricted eating, which in lay terms is sometimes called intermittent fasting when it’s really not, there are fewer side effects or risks because the fasting is a little bit less,” she explained.
In Summary
Experts say the body is designed to need a break from eating to rest and repair itself. Cutting the amount of time we eat in the day helps that process.
New research finds that fasting for 24 hours once or twice a week is associated with improved metabolic health.
They also say that reducing refined sugar and processed food intake can help maintain our metabolic health to reduce disease risk.
