- Many people are doing intermittent fasting wrong, a weight loss researcher says.
- Fasting mistakes like eating junk food can leave you feeling deprived and missing out on benefits.
Intermittent fasting can be a powerful tool to help you burn fat and lose weight while feeling less hungry, but you're probably doing it wrong, according to a weight-loss researcher.
To get the most out of fasting, pay attention to what you're eating first, said Dr. Paul Arciero, health professor at Skidmore college and author of The Protein Pacing Diet.
His research has designed a specific fasting routine, and evidence suggests it can help people burn fat faster than calorie counting alone. The findings were published December 2022 in the journal Obesity.
"We have data to show it's not about the total number of calories we consume. Now it comes down to the quality of the nutritional intake and the patterning," he told Insider.
By adding more protein and fiber, timing your meals right, and cutting back on sugar, you can see better results and fewer side effects from fasting, Arciero said.
Fasting before you have a healthy diet routine can backfire
Before you can even think about intermittent fasting, it's important to follow some basic habits of healthy eating already, according to Arciero.
"If they have a poor diet going into it, it's not going to serve them well," he said.
Create a habit of protein pacing — eating enough protein and including multiple sources of protein throughout the day — for a few weeks before you attempt fasting, Arciero recommends.
Otherwise, any unhealthy habits you have will offset the benefits of fasting, like better blood sugar control, since you're likely to go right back to eating junk food when the fast ends.
Don't eat junk food after a fast
The biggest mistake most people make with intermittent fasting is thinking they can eat anything, as long as they stick to the fasting window, Arciero said.
This can lead to cycles of deprivation and bingeing which can be counterproductive to health, according to Arciero.
"It's a disordered eating pathology. Why would we ever want to highlight that as helpful?" he said.
Instead, you should aim to get more fiber and protein into your snacks and meals both of which can help you feel full and support a healthy digestion. It's also important to cut back on sugar, especially added sugar, Arciero said, because too much of it can disrupt your metabolic health, the opposite of your goal while fasting.
Avoid skimping on protein
Arciero's research found people had better results from intermittent fasting if they ate high-protein meals at least four times during their eating period.
Previous studies suggest protein can help you feel more satisfied after eating and may even help you burn more calories, since it takes more energy to digest protein compared to other nutrients like carbs or fat.
It's also a crucial nutrient for maintaining muscle, which is important for a healthy metabolism. Some fasting diets have been linked to a higher risk of muscle loss, so the additional protein may help.
Water-only fasting can be less effective
It's a misconception that you can't consume anything during a fast. You can get the benefits of fasting while having a small amount of calories from coffee, tea, and beverages that contain electrolytes, Arciero said.
His fasting group in the study ate around 400 calories a day, split into small portions of high-fiber and high-protein supplements every four hours. However, they stuck to very specific foods like bone broth, low-glycemic protein crackers, and tiny portions of nuts and seeds — sneaking a handful of potato chips or bite of ice cream doesn't count as fasting.
"We don't allow nibbling," Arciero said.
Other advocates of fasting say you can enjoy bone broth and Bulletproof coffee, or other low-carb options that can help you avoid spiking your blood sugar to maintain the fast.
Fasting isn't about being hungry
A striking result of Arciero's research was that people who had the best results while fasting were also less hungry — something that was initially a surprise, but has been the consistent result in his other studies.
The combination of protein, fiber, and timing in the study is "very unique," he said, and more research could help us better understand how it can support the benefits of fasting.
"People think that the only way to reduce the hunger signal in our brain is to flood it with energy, and nothing could be further from scientific truth," he said.
Along with debunking the idea that you have to deprive yourself to fast, Arciero also noted the benefits go far beyond fat-burning, and can help with longevity, lower risk of illness, and overall wellbeing.
"We're really focused on the health and performance benefits," Arciero said. "The side effect, as we call it, is weight loss. In our work, it's just a wonderful icing on the cake."