Intermittent Fasting: What You Should Know
People fast for many different reasons. For instance, one usually fasts the night before they have surgery, and before some medical tests, too. Of course, many of us have that one friend who boasts they fast three or four times a week to stay thin. It seems outrageous to go that long without food, but there is a trend in the world of healthy eating called intermittent fasting.
It’s actually a new, old trend because people have been doing it for years, some without even realizing it. Grandma used to tell you not to skip meals, but maybe she was wrong.
What are the intermittent fasting benefits and negatives?
Let’s start with the basics. What is intermittent fasting? Put simply, intermittent fasting is a strategy for controlling calorie intake. Food is energy measured in units called calories. Your body needs a certain number of these calories just to function, but it doesn’t need more than that number, and that’s what trips most people up.
The human body comes with an internal mechanism that promotes survival. In other words, it does things like save calories for a rainy day to make sure you always have the necessary energy to survive. That bank of calories is what people call excess fat.
When you reach the number of calories you need, your body takes what is left over, converts it into fat, and puts it away for later, usually around your waist, thighs or backside. On those days when you don’t have enough calories, it dips into that savings account and converts some fat back into energy, which is the basis for weight loss.
Calorie Use and Aging
It’s a very efficient system until you start to get older. At that point, your body doesn’t burn those calories at the same rate, so even if you are eating the same as you did your whole life, fat starts to build up. Intermittent fasting has become a trending fad that adults of all ages, especially those who reach the 50-year milestone, use to try to reduce their calorie intake.
Intermittent Fasting 101
Intermittent fasting is a broad term, so technically, unless you have food in your mouth 24 hours a day, you already do it. When you go to bed, you fast until morning, which is why that first meal of the day is called breakfast. Intermittent fasting means to have set periods of time you eat and that you don’t eat.
- Whole day fasting – Typically involves one day on and one day off from eating. Every other day is a fasting day.
- Time-restricted feeding (TRF) – Eating only a certain number of hours a day. For example, you might fast for 23 hours a day and just eat for one.
Intermittent fasting is about food and calorie restriction, not fluids. During the fasting period, you drink lots of water, coffee, tea and any other zero calorie drink you want including diet soda. It seems extreme, but there are some potential intermittent fasting benefits, especially when it comes to heart and brain health.
What Science Says About Intermittent Fasting
From the outside looking in, it seems like going long periods of time without eating couldn’t possibly be good for you, but what do the scientists say about this practice? It’s pretty much all good if done responsibly. Mikel Bryant, a dietitian with the Mayo Clinic, says fasting is a tool that can benefit some people as they try to drop those extra pounds.
The jury is still out on this practice, but there is evidence to show intermittent fasting benefits for those who are healthy. A 2005 study published in The Journal of Nutritional Biochemistry found that intermittent fasting did improve the health of those who are overweight. It also extended the lifespan of animals. The study authors state this eating strategy potentially:
- Enhances cardiovascular function
- Improves brain function
- Reduces the risks of coronary artery disease
- Reduces the risk of stroke
- Lowers blood pressure
- Increases insulin sensitivity
- Reduces the effects of aging
A second study in 2006 focused specifically on the neurological benefits of intermittent fasting. The researchers found it could potentially prolong the health-span of the nervous system in a way that might reduce incidents of brain diseases.
More recently, a study published in Nutrition Reviews found alternate day fasting did lead to weight loss in those who were clinically obese. There was also an improvement in critical health biomarkers such as:
- LDL cholesterol
- Insulin sensitivity
- Blood pressure
You know, all those things people start to notice as they get older.
When Intermittent Fasting Isn’t the Right Choice
The caveat that comes with intermittent fasting is that it is an unhealthy choice for some people. It’s not right for anyone with diabetes, for example. It would also not be practical for someone who is very active. You need fuel to jog daily, for example. If your work is physically challenging, you need calories to get through the day.
You would also want to avoid restrictive calorie diets if you have a history of eating disorders. It is likely fasting is a trigger.
Smart Intermittent Fasting
Next, evaluate your diet. If you are going to fast, make healthy choices when you do eat:
- Whole grains
- Lean protein
Drink plenty of water and fluids each day to avoid dehydration, too.
If you are currently overweight or have a history of yo-yo dieting, don’t skip breakfast even on fasting days. You don’t have to eat much, but do eat something. Skipping breakfast is possibly linked to obesity.
You might need to adjust your exercise schedule, too. Avoid excess activity when fasting.
Finally, start slowly and build. You can’t go from eating 2,500 calories a day to eating 2,000 every other day. That’s a recipe for failure. Instead, start fasting for hours at a time and build to let your body and mind make the adjustment.
Intermittent fasting is not the worst idea if you are looking to lose weight or maintain your healthy one. That’s especially true if you are over 50 and need to make a change to avoid that middle-age spread. Just be smart about it, and talk to your primary care doctor so you know it’s safe for you.