Diets 101: Intermittent Fasting
There are so many diets out there and it’s often hard to find good information about whether or not these diets are worth trying. You’ve likely heard of intermittent fasting (IF) and wonder if it’s a good option. Today I’ll discuss what it is and the research behind it to help you make an informed decision about whether or not it’s a good plan for you and your health goals.
What is intermittent fasting?
Rather than telling you exactly what to eat, IF focuses on when to eat. Fasting has been around for thousands of years, but there are several different types of fasting that have become popular today. The idea behind IF is that you eat for a set period of time, then fast. Fasting will allow the body to switch from burning carbohydrates to burning stored fat. When a person eats every few hours during the day, they tend to only burn the carbohydrates that are being eaten rather than the fat that has been stored up. The idea is that burning fat for fuel may have health benefits.
Types of fasting
There are several different approaches to fasting; some examples are:
Time-restricted: The 16:8 approach is fasting for 16 hours each day, then eating for 8 hours; for example, you may eat from 12 pm-8 pm, then fast until noon the next day. Another less strict option is fasting for 12 hours each day, so you may start eating at 7 am and stop at 7 pm.
Alternate-day: The 5:2 approach is when you eat normally five days of the week, then limit yourself to one 500-600 calorie meal on the other two days.
Whole-day: Whole-day fasts can last for 24-72 hours and often include no food intake other than water, though there are variations that include small amounts of food.
Pros
There are several studies that support the use of IF for improving health. Possible benefits of IF include:
Improved mental and physical performance: Burning fat for fuel instead of carbs may have beneficial effects on brain function and may reduce inflammation in the body, though more research is still needed.
Weight loss: While fasting, the body is using fat stores for fuel instead of carbs, which could potentially lead to weight loss, though this is also based on the type and amount of foods consumed during eating period. Being forced to stop eating by a certain time to start fasting can reduce calorie intake, especially at night, thus leading to weight loss.
Reduced aging: Fasting may prevent or reduce cell breakdown, which could possibly slow down the aging process.
Reduction of risk factors for diabetes, heart disease, cancer, high blood pressure, and high cholesterol: More research however is needed and it is important to consider that type and amount of foods consumed and other lifestyle factors will also play a role in determining risk for chronic disease.
Overall, more research is still needed to determine if IF is beneficial for improving health.
Cons
If you tend to be starving the moment you wake up IF may not be the plan for you. The 16:8 plan, for example, involves eating for only 8 hours each day. If you decide to follow this plan and eat only from 12 pm-8 pm, you’ll likely be miserable each morning and overeat once you’re able to eat. Hunger during the fasting period can lead to irritability, fatigue, and trouble concentrating.
The timing of exercise should also be considered when planning a fasting schedule. Exercising at the beginning of the fasting period may pose challenges because of the length of the fast, so it is usually recommended to time exercise at the end of the fast or during the eating period.
Additionally, as with any eating plan, one must evaluate if it is sustainable long-term. I like to emphasize the importance of finding a plan that will work over a lifetime rather than just for a few months. Changing habits by making small lifestyle changes may take longer for you to achieve your health goals, but in the long run it will help you to be much more successful.
Other considerations
Intermittent fasting does not specify what to eat; therefore, if you decide to try IF for weight loss, it is important to also look at what you are eating. IF alone will not lead to weight loss if you aren’t also making healthy food choices. If you decide to try IF, I’d recommend looking at the Mediterranean diet for ideas.
IF is not necessarily safe for everyone, so always talk with your doctor if you have questions. It is recommended for the following groups to avoid IF:
Children and teenagers
Pregnant or breastfeeding women
Those with a history of eating disorders
Overall, I recommend looking at the pros and cons of IF before trying it out yourself. It’s best to talk with your doctor or a registered dietitian to see if it is the best plan for you. Be sure to check out my other posts about popular diets and stay tuned for more!
