I’m a dietitian — here’s the secret to intermittent fasting

Intermittent fasting might help you lose weight — but only if you adhere to some strict guidelines, says one dietitian.

“You can’t just eat what you want with intermittent fasting if you want to lose weight. You have to eat balanced meals during the feeding period,” Rob Hobson, a registered dietitian, told the Daily Mail.

Although research is ongoing, intermittent fasting — which has adherents restricting their calories during certain times of the day or on certain days of the week — fans say the diet has done wonders for their gut microbiome and has helped them to lose weight.

“Some of the strongest research for fasting is around the potential to reduce insulin resistance and lower the risk of type 2 diabetes,” Hobson noted. He went on to explain other potential benefits, which include reducing oxidative stress and inflammation, lowering cholesterol and blood pressure, and protecting brain health.

But other recent studies have shown the opposite. In fact, a study from March claimed that those who restricted themselves to only eating during eight hours each day had a 91% higher risk of dying from heart disease.

Regardless of which studies you may read, intermittent fasting may not work — or even be right — for everyone. So should you try this popular style of dieting? Here, five tips to making intermittent fasting work, and how to know if it’s right for you.

Pick a fasting style that works for your schedule

Intermittent fasting is actually an umbrella term that encompasses several styles of eating. In some, you’ll fast during certain times daily and in others, you’ll fast for one or two days per week.

Hobson outlines four popular types of intermittent fasting.

The first is 16:8 — where you’ll only eat during eight hours per day and fast for the other 16 hours. This style might work well for parents on the go, Hobson said.

For example: You’re up early with the kids, and amid the morning rush to get them to school and yourself to work, you skip breakfast. Soon, it’s 10 a.m. and you’re ready for food. At the end of the day, you’re having dinner with your kids by 5:30 p.m. so they can make it to bed on time.

“Without realizing it you are already conforming to the 16:8 method of fasting — only consuming food within an eight-hour window,” Hobson explained.

The 16:8 method might also be good for gym-goers and people who have demanding work schedules, Hobson noted.

Two other closely related styles of the diet are called the “twice-a-week method” or “alternate-day fasting.” In both of these methods, you’ll eat normally for several days per week and then only eat 500 calories on certain days. For the twice-a-week method, you’ll eat 500 calories on two non-consecutive days (like Mondays and Wednesdays, for example). In the other version, you’ll restrict yourself to just 500 calories every other day.

For reference, 500 calories isn’t much. A breakfast that consists of a two-egg omelet made with a few ounces of mozzarella cheese, a slice of whole wheat toast and a cup of blueberries could be roughly 500 calories — and that’s all you’d get for the day.

This style of dieting might work well for older folks, Hobson noted, who may need fewer calories anyway because they’re less active. Plus, our appetites tend to diminish as we get older.

If that style of dining doesn’t sound appealing, you could opt for the last style of fasting: a true 24-hour fast, completed twice weekly. This means no food, and only water for a full day.

If you’re opting for one of the reduced calorie fasts, plan to pack your snacks with protein and fiber to keep you feeling full as long as possible. Hobson advised.

Understand that it might take some time to adjust

Not surprisingly, intermittent fasting can take some time to get used to. You’ve probably heard of “hanger” — where you might feel angry because you’re hungry — but have you heard of “fanger”? That’s fasting-induced anger, and it could be a new reality for you, at least initially.

Having low blood sugar can lead to irritability and mood swings, while fasting can also lead to a cortisol response — a stress hormone — which might leave you feeling anxious at first.

The good news is that your body typically adjusts, Hobson explained, and those feelings should subside if you stick with the diet.

Drink lots of water

We get roughly 20% of our daily fluid intake from food, according to the Mayo Clinic. So if you’re cutting out all or most of those calories, you’ll need to supplement by drinking extra water or other liquids.

How much water you need will depend on your age, sex and activity levels, but in general, men should aim for about 15.5 cups (just under 4 liters); and women need about 11.5 cups (or a little under 3 liters).

You’ll know you’re hydrated when you rarely feel thirsty and when your urine is colorless or pale yellow, the Mayo Clinic says.

Time your exercise with your fasting

It’s probably not surprising, but if you’re not eating for large portions of your day, you’ll need to time your workouts just right so you have the energy to complete them.

If you’ll be weight lifting, time your workout to be at the end of your fasting window, according to the Daily Mail. So if you fast overnight and eat from 8 a.m. to 4 p.m. each day, time your workout to wrap by 8 a.m. Then follow your strength sessions with 20 to 25 grams of protein, to ensure that your muscles have been adequately fueled.

On the other hand, if you’re doing cardio, work out at the end of your eating window. So if you’re eating from 8 a.m. to 4 p.m., you should do your cardio in the evening, after 4 p.m., according to the Daily Mail. You should also plan your last meal around carbohydrates so that you’ve got plenty of fuel for the cardio workout ahead.

Know that this diet is not right for everyone

Intermittent fasting in any style is hardly a magic bullet style of dieting. In fact, there are certain groups that should avoid this style of eating entirely. Children and teens, for example, whose bodies are still developing and whose bones are still growing should not fast.

Pregnant women and breastfeeding women, as well as those recovering from an illness or injury, may not want to fast at all. Fasting can affect hormone levels, although some studies have shown that it may help alleviate PMS symptoms in some women.