Common Myths with Time Restricted EatingFeb 16, 2022
Time-restricted eating and fasting seem to be the latest "diet trend.” Instead of telling you what to eat, intermittent fasting tells you when to eat. I wrote a blog about the benefits of time-restricted eating in the past (https://sarahsmithmd.com/basics-of-time-restricted-eating-as-a-tool-for-weight-loss/). Today I am reviewing some of the myths that surround this way of eating.
Breakfast is the most important meal of the day.
The mantra of breakfast being the most important meal of the day has been ingrained in most of us since an early age. Unfortunately, this advice is not backed by science. The main studies that are used to support this are observational. A recent meta-analysis of randomized clinical trials found that those assigned to skip breakfast ate less overall and lost more weight than those eating breakfast.
When you first wake up, your insulin level is often low, and you might be just starting to burn fat for energy. Eating first thing in the morning raises insulin and glucose and immediately shuts off fat-burning. If you push your first meal a few hours later, you can burn body fat longer, and if you are fat adapted your appetite may be lower.
Fasting leads to burning muscle instead of fat.
Many people are concerned that if they start fasting, they will either stop making muscle or maybe even burn through their muscle. If you are underweight, this may be true, but otherwise is not. In fact, growth hormone (an anabolic, muscle building hormone) is increased during fasted states, which can help preserve and even build muscle.
Fasting slows down metabolism.
There are many studies that show fasting up to 72 hours does not slow down metabolism at all and in fact might speed it up slightly thanks to the release of catecholamines and activation of the “fight or flight” system. A 2016 study that directly compared the metabolic effect of chronic calorie restriction to alternate daily fasting showed that chronic calorie restriction causes a statistically significant slowing of metabolism that was not seen with alternate day fasting.
If you do not eat, you will get low blood sugar.
Healthy people who have no underlying medical conditions and who are not taking any diabetes medications can fast for long periods of time without suffering from low blood sugar. If you are diabetic or prediabetic on medications, you should check with your doctor before starting on a fasting program.
Fasting is dangerous.
Fasting is a normal part human history; nearly every religion has periods of fasting. When we were hunter-gatherers, fasting was a regular part of life. When we eat, we store food energy or calories as body fat. When we fast, we burn body fat. However, there are some people who should avoid fasting including anyone under 18 years old, pregnant or breastfeeding women, those who are underweight, or those with a history eating disorders.
DISCLAIMER: Sarah Smith MD is a medical doctor, but she is not your doctor, and she is not offering medical advice on this website. If you are in need of professional advice or medical care, you must seek out the services of your own doctor or health care professional.