Intermittent Fasting: Is It Safe for Older Adults?

  • Intermittent fasting is a restricted calorie intake diet that promotes fasting.
  • The results of intermittent fasting on younger and middle-aged adults are positive but further studies are needed for the older adults.
  • Older adults who are under medication for heart problems and diabetes should consult with a doctor before trying intermittent fasting.

With today’s increasing health concerns, people are looking for ways to lose weight, lower inflammation, LDL “bad” cholesterol levels, blood pressure and heart rate, reduce insulin resistance, and increase “good” HDL cholesterol. 

A lot of diets have been tested out and one of the most popular is the intermittent fasting.

Although studies are still limited, meal and calories restrictions, or when to eat and how much to eat, have proven to be effective for weight loss and decreased the risk of developing various diseases in some studies while other studies showed an improved memory.

However, the data is only based on the effects of intermittent fasting on young and middle-aged adults and not on older adults.     

How does intermittent fasting work?

Intermittent fasting restricts the number of calories that one can consume in a day and the duration or time when you are allowed to eat. 

Here are the different approaches:

Alternate-Day Fasting or Eating Every Other Day.

Eat a normal load every other day and just 25% of your daily calorie needs, in one meal for the days in between.

Sample: Monday, Wednesday, and Friday: 1,800 calories; Tuesday, Thursday, and Saturday: 450 calories only

5:2 Approach

Eat normal load of calories for 5 straight days; Next two days, just 400-500 calories per day

16:8 approach

Every day, eat a normal number of calories for an 8-hour period and fast for the next 16 hours.

Sample: Eat from 9am-5pm then fast from 6pm to 8am.

Intermittent Fasting Benefits

Registered dietitian Kathy McManus, director of the Department of Nutrition at Harvard-affiliated Brigham and Women’s Hospital explains that, “Fasting leads to lower levels of glucose [blood sugar].

In response, the body uses fat instead of glucose as a source of energy, after turning the fat into ketones.” This metabolic shift of using glucose to ketones as the body’s source of energy is a healthy way of changing the body’s chemistry.

In animals, doing regular fasting results in weight loss which lowers insulin resistance, lowers “bad” cholesterol levels, blood pressure and heart rate, less inflammation, and increases “good” HDL cholesterol levels.  In some studies, memory is also improved, and prolongs life span.

Dr. William Mair, a researcher and associate professor of genetics and complex diseases at the Harvard T.H. Chan School of Public Health explains that “By eating in the day, you’re not challenging the mitochondria (energy-producing engines) at night, when they’re supposed to be doing other things.”

Dr. Mair added, “But we have many unanswered questions.”

There is a need for studies to be done on older adults and its possible risks.

If you want to try intermittent fasting, talk with your doctor first.  Those who have heart disease or diabetes especially need to consult with a doctor.

For diabetics who are under medication for their blood sugar and require food at regular periods, intermittent fasting might be harmful.

“People who need to take their medications with food — to avoid nausea or stomach irritation — may not do well with fasting. Also, people who take heart or blood pressure medications may be more likely to suffer dangerous imbalances in potassium and sodium when they’re fasting,” according to Dr. Suzanne Salamon, associate chief of gerontology at Harvard-affiliated Beth Israel Deaconess Medical Center.

Dr. Alexander Soukas, an endocrinologist and molecular geneticist with Harvard-affiliated Massachusetts General Hospital says, “Taking medications doesn’t break the fast, and neither does having calorie-free drinks like water or black coffee.”

McManus says, “If you’re already marginal as far as body weight goes, I’d be concerned that you’d lose too much weight, which can affect your bones, overall immune system, and energy level.”

Dr. Salamon says, “Perhaps you can try a modified fast. I suspect it would still do a lot of good for people who are overweight. Just work with your doctor on a plan that will benefit your health without risking it.”

Source: Harvard Health



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