What is Intermittent Fasting?

New year, new me? It’s a popular pledge during January as people will crowd into fitness centers to start the year fresh and healthy. While exercise is a critical part to improving your health and shedding a few pounds, a balanced and nutritious diet is also an important factor.

There’s a new diet for every situation now, but one that has started to gain popularity is intermittent fasting. It is always recommended to talk to your primary care provider or a registered dietitian before starting a new diet.

Intermittent fasting means that you rotate periods of eating with periods of not eating. There are different ways that you can do intermittent fasting. These include alternate day fasting, modified fasting, and time-restricted eating.

Alternate day fasting means you have days when you eat and days when you don’t eat. You can have calorie-free fluids such as water, tea, and black coffee. Some folks will eat for five days and fast for two days.

Modified fasting is when you restrict your caloric intake by a certain percentage, say 20 to 25 percent on fasting days. Others will restrict their caloric intake to only 500 calories on fasting days.

Time-restricted eating refers to having periods of time when you and then periods of time when you fast. A popular time-restricted fasting method uses 16 hours of fasting with an eight-hour eating window. Thus, if you started eating at 10 a.m. you would stop eating at 6 p.m. and not eat again until 10 a.m. the next morning.

That doesn’t mean eating whatever you want, but the theory behind fasting is that it allows insulin levels to drop and cells to release stored glucose as energy. It also kicks your body into burning fat for energy. As mentioned previously, you still want to think about your food choices and include plenty of vegetables, whole fruit, whole grains, lean sources of protein, and heart healthy fats into your meal plan. Water is also vital.

Intermittent fasting is thought to be beneficial for weight loss and lowering blood pressure as well as cholesterol and lipid levels. Studies are not conclusive and more research needs to be done. We do not know the long-term effects of intermittent fasting.

At this time intermittent fasting is not recommended for people with diabetes, particularly those who are taking medication. I also would not recommend it for those who are pregnant and/or breastfeeding. People with a history of an eating disorder are also not advised to follow this type of eating plan.

The bottom line is that intermittent fasting has shown promise with helping people lose weight and improve their blood pressure and cholesterol levels. It may also help to improve mood, but more research is needed.

With any diet or lifestyle change, you want to think about your food choices and make sure you are choosing a nutrient-rich diet to prevent nutrient deficiencies.

Kim Westcott, MS, RD, LDN, board certified specialist in oncology nutrition at Beebe’s Tunnell Cancer Center and has been a registered dietitian at Beebe Healthcare since 1993.