This week on fad diets: Intermittent Fasting, IF. If you haven’t heard of this new fad diet, consider yourself lucky. This diet had been made famous by people like Doctor Oz and other health “influencers” that rarely if ever delve into the research before promoting a diet like this. If you were to google this diet you would likely come up with a bunch of “claimed health benefits” like, weight loss, better glucose management, and even anti-aging. Can we be realistic here? Anti-aging? If a diet sounds like a scam, it likely is. Please use your intuition and common sense when you stumble upon fad diets. So, in this blog, I will explain the three most common types of fasts.
- 5:2 Fast: With this type of IF you eat like “normal” 5 days of the week and then only eat 500-600 calories for 2 days of the week
- 8 -hour window: With this form of fasting you have an 8- hour window to eat and then you fast for the next 16 hours. Meaning, if you’re first meal is at 9 am, your last meal must be at 5 pm.
- 24-hour fast: You cannot eat anything or drink anything with calories for 24 hours once or twice a week.
So, most people with a healthy metabolism need to eat about every 4 hours. Granted, this doesn’t mean they eat an entire meal every four hours, rather small snacks between meals. So, what this looks like: breakfast at 6 am, snack at 10 am, lunch at 1 pm, snack at 4 pm, and dinner at 7 pm. This gives the body food at regular intervals across your day. The body LOVES this. If you go more than 5-6 hours without food, this may result in poor blood glucose levels, and then almost certainly, overeating at your next meal. If you wait that long before eating because someone told you that snacks are “bad” you will almost certainly consume more calories at your next meal than if you simply had a snack when you were hungry. With intermittent fasting, you are ignoring your body’s primal hunger cue. When doing this, your brain doesn’t know you are intentionally starving it, so it will automatically slow down the rate of metabolism to compensate for the lack of food it’s getting. Sounds counter intuitive right? When your body is hungry it means your metabolism is off and running and ready to burn more fuel. If you feed your body nourishing whole foods when it is hungry, you will find you’ll have more energy throughout your day, making you feel better.
People who do intermittent fasting likely experience “brain fog”, lethargy, insatiable cravings, and hormonal imbalances. All for what? To lose a few pounds? Does that sound worth it to you? So what people need to know is that there have been NO long-term studies proving the long-term benefits of intermittent fasting. Would you follow a diet that has only been tested in the short term in rats? There have been a few studies with men and women, but again, they were short term with a small sample size (inconclusive research). One of the studies found that women who did IF had higher blood cortisol levels than women who ate when they were hungry and stopped when they were full. Cortisol is a stress hormone that can wreak havoc on the female reproductive system. With the lack of good, long term research out there I cannot ever recommend doing intermittent fasting. If your goal is to lose weight and feel better, have you tried basing your meals off MyPlate? Meaning, half your plate fruits and veggies, a quarter lean protein, and a quarter whole grains. I guarantee if you try MyPlate and eat at regular intervals you will feel better and may even lose weight, in a proper, sustainable method. As always, if you have any questions, feel free to contact your local Registered Dietitian and please do not seek out advice from celebrity influencers who have one thing in mind when promoting your health: money.
Reference:
- Nakamura Y, Walker B, Ikuta T. Systematic review and meta-analysis reveals acutely elevated plasma cortisol following fasting but not less severe calorie restriction. Stress. 2016;19(2):151-157. doi:10.3109/10253890.2015.1121984
-Written by Sami Kratovil, SDSU Dietetic Student
