As interest keeps growing in intermittent fasting, so do the questions about how to get the most out of the weight-loss strategy.
Intermittent fasting also doesn’t lead to eating disorders or slow down a person’s metabolism, said Krista Varady, a professor of nutrition at the University of Illinois, Chicago, who has been studying fasting for almost 15 years and offers tips about it on her Instagram page.
She’s the co-author of a 2022 review of studies that found intermittent fasting is generally safe and produces few gastrointestinal, neurological, hormonal or metabolic adverse effects.
Her previous research showed obese people who followed the 16:8 fasting regimen for three months modestly lost weight and lowered their blood pressure without feeling hungry or deprived.
Varady dabbles with intermittent fasting herself, typically for a few weeks after the holidays to lose a few pounds. The 16:8 plan is less intense than the other plans, but if she wants a more rapid weight loss, she’ll opt for alternate day fasting.
“The first five fast days are pretty tricky, but once your body gets adjusted to that kind of up-down pattern of eating, it actually gets really easy,” Varady told TODAY.
So how do you boost your chances of intermittent fasting success?
First things, first:
Always check with your doctor before starting a diet.
Intermittent fasting is not for everyone, including:
- Children under the age of 12.
- Adolescents who are normal weight.
- Women who are pregnant or lactating.
- People with a history of eating disorders.
- Individuals with a body mass index below 18.5.
- People over the age of 70, because fasting may exacerbate muscle wasting in this population, Varady said.
- People with Type 1 diabetes.
Consider the intermittent fasting plan right for you:
Some of the popular regimens include:
Here are more tips to keep your plan on track:
1. How can I suppress hunger during intermittent fasting?
- Eat high-fiber foods, such as nuts, beans, fruits and vegetables and high-protein foods, including meat, fish, tofu or nuts, during your eating window, Varady advised. Chewing high-fiber gummies can also help.
- Drink lots of water. People tend to think they're hungry, when they are really just thirsty, she said.
- Go for black coffee or tea, or cinnamon or licorice herbal teas. These beverages may have appetite-suppressing effects, Varady noted.
- Watch less TV. “I know this sounds strange, but while you are watching TV, you are bombarded with dozens of ads for food. This can make you feel hungry, when in actuality, you are not hungry at all,” she said.
Remember, being "a little hungry" is the best thing that can happen to you, wrote Madelyn Fernstrom, health and nutrition editor at NBC News, calling it a "true mind-body connection" that helps you recognize fullness.
2. When should I exercise?
When Varady and her colleagues conducted a study that combined alternate day fasting and exercise, they allowed the participants to pick whether they wanted to exercise on a feasting or fasting day, and found there was no strong preference one way or the other. But the researchers were surprised the dieters actually reported feeling more energetic on fasting days.
That being said, exercise before you eat because people get hungry about half an hour after they finish working out and may find it too hard to stick to their plan if they can’t eat anything at all afterwards, Varady noted.
If you’re on the 16:8 plan, exercise before or during your eating window. If you’re doing alternate day fasting and are exercising on your 500-calorie day, save food for after your exercise session.
3. Is it OK to skip breakfast?
Yes, Varady said. The notion that omitting a morning meal is bad for your waistline likely began with studies sponsored by cereal companies, and most of that research looked at the effects of breakfast skipping on cognition in children, she noted: “I’m not sure how that all got translated to body weight.”
Indeed, a 2015 study found breakfast may not be the most important meal for weight loss.
Another analysis, by obesity and nutrition researcher David Allison, found there wasn’t scientific data to definitively support a link between eating breakfast and weight loss, or skipping breakfast and weight gain.
4. How do I combat feelings of low energy or low focus during fasting?
- Try drinking black coffee: It helps improve concentration and energy, and has no calories in it, Varady said.
- Take a deep breath and give yourself a break: Mindfulness and a bit of meditation can go a long way in helping to make you feel better during the fasting period.
5. Can I have alcohol?
Yes, but don't drink any alcohol during a fasting window or a fasting day since it's high in calories and has no nutritional value, Varady noted. During non-fasting periods, women should limit their alcohol intake to one drink a day; men shouldn't have more than two.
6. Does fasting benefit people who don't need to lose weight or who have reached their goal weight?
Yes, Varady said, citing one of her studies that found fasting helps maintain a healthy body weight; lowers triglycerides, which is important for heart health; helps decrease blood pressure and improves blood sugar regulation.
A review of research in humans and animals, published in 2019 in the New England Journal of Medicine, found intermittent fasting has "broad-spectrum benefits" for health problems including obesity, diabetes, heart disease, cancer and neurologic disorders.
The powerful health effects appear to come from the body flipping a "metabolic switch" during fasting — or shifting away from using sugar as its main source of energy and instead converting fat for fuel when a person's stomach is empty.