Updated: May 11
One of the most popular trends in dieting over the past few years is intermittent fasting. And let’s be clear hear, this is definitely a diet. Just do an internet search for “The Every Other Day Diet” or “The 16:8 Diet” – diet is right there in the name.
While early research has shown weight loss and improved chronic disease risk with intermittent fasting, there is no long-term evidence to suggest that this diet is any more sustainable than any other restrictive diet.
A few points worth noting:
- I believe there is a benefit in cycling the body through a fed and fasted state. Our metabolisms are designed to balance blood sugar and energy levels throughout the day whether we’ve just eaten or we’re about to eat. If you find that you’re eating more frequently then every two or three hours you may not be allowing your body to move through its natural hormonal cycles. And frequent snacking may also diminish hunger and fullness signals making it more difficult for you to recognize when you’ve had enough to eat.
- Although I haven’t seen any research to support this theory, I’ve often hypothesized that men may be more suited to fasting than women. Remember that women’s bodies are designed to grow and feed babies which requires regular energy. And from a historical perspective, men traditionally hunt or farm. If you’re out in the fields all day you probably aren’t eating three meals plus snacks.
- *One appealing component of IF is that you can eat whatever you want. There aren’t any off-limits foods. Allowing yourself to eat the foods you enjoy is critical to sustaining any long-term nutrition plan.
*Don’t fool yourself into thinking that intermittent fasting and intuitive eating are one in the same simply because you can eat whatever foods you want. Restricting intake through fasting is in direct contradiction to several intuitive eating principles.
So ok, intermittent fasting might not be the most terrible diet ever. But it’s still a diet, and diets are still the worst. Here are just a few fasting related negatives:
Breakfast Skipping: One of my biggest concerns about a 16:8 approach to intermittent fasting is that it almost always results in breakfast skipping. If you’re only eating from 11 am to 7pm you aren’t going to eat breakfast. You’ve probably heard that breakfast is the most important meal of the day and as it turns out that’s true. There’s a ton of research linking breakfast-skipping with increased disease risk. Sure, studies on IF have shown improvement in cardiovascular and diabetes risk factors. But eating breakfast has also been shown to be cardioprotective and improve insulin and blood sugar levels. So yeah, just eat breakfast.
Ignoring Hunger and Fullness Cues: If you’re fasting, you’re hungry. Guys, this part’s important – Hunger is an essential biological function that reminds us we need to eat to stay alive. When you ignore your hunger, your body assumes there must not be any food around and your metabolism starts to slow down. If you ignore your hunger on the regular, it becomes more difficult to feel the physiological signs of hunger. You don’t recognize you’re hungry until you’ve tapped into your primal fear of starvation. Primal hunger results in an uncontrollable desire to eat. And because intermittent fasting allows unlimited eating within a window of time, the inclination will be to eat excessively during that time. This means you’re much more likely to eat past fullness to the point of discomfort. And voila! Now you’ve lost your innate human ability to regulate intake.
Instead of relying on hunger and fullness sensations to guide eating, you’re watching your clock. But no matter how advanced your Apple Watch technology, it doesn’t know when you’re hungry!
Double Dieting: One diet is bad enough but lately I’ve seen more and more nutrition professionals recommending intermittent fasting in conjunction with eating more nutritious or “clean” foods and less sugar. Um, what?!? The whole point of fasting is that you can eat whatever you want the rest of the time! As a practitioner, I’ve found intermittent fasting in conjunction with low carb/low sugar/“clean” eating to be especially problematic. My clients feel hungry for 16 hours and deprived for 8 hours. Often, people superimpose intermittent fasting on top of another diet without even realizing they’re doing it. No, no, no! The last thing anyone needs is more restriction.
Sure, the buzz around intermittent fasting may sound good. But we’ve heard this before. Low calorie, low fat, plant based, Whole 30, and on and on. Initial weight loss followed by increased weight gain with long term metabolic and psychological consequences. Sound like just another diet to me.
Bi, Huashan, et al. “Breakfast Skipping and the Risk of Type 2 Diabetes: a Meta-Analysis of Observational Studies.” Public Health Nutrition, vol. 18, no. 16, 2015, pp. 3013–3019., doi:10.1017/s1368980015000257.
Gabel, Kelsey et al. “Effects of 8-Hour Time Restricted Feeding on Body Weight and Metabolic Disease Risk Factors in Obese Adults: A Pilot Study.” Nutrition and Healthy Aging 4.4 (2018): 345–353. PMC. Web. 14 Sept. 2018.
Ganesan, Kavitha, Yacob Habboush, and Senan Sultan. “Intermittent Fasting: The Choice for a Healthier Lifestyle.” Ed. Alexander Muacevic and John R Adler. Cureus 10.7 (2018): e2947. PMC. Web. 14 Sept. 2018.
Jakubowicz, Daniela, et al. “Fasting Until Noon Triggers Increased Postprandial Hyperglycemia and Impaired Insulin Response After Lunch and Dinner in Individuals With Type 2 Diabetes: A Randomized Clinical Trial.” Diabetes Care, vol. 38, no. 10, 2015, pp. 1820–1826., doi:10.2337/dc15-0761.
Leiva, Courtney. “Everything You Need to Know about the 16:8 Principle - the Most Common Form of Intermittent Fasting.” INSIDER, INSIDER, 12 Sept. 2018, www.thisisinsider.com/16-8-intermittent-fasting-2018-9.
St-Onge, Marie-Pierre, et al. “Meal Timing and Frequency: Implications for Cardiovascular Disease Prevention: A Scientific Statement From the American Heart Association.” Circulation, vol. 135, no. 9, 2017, doi:10.1161/cir.0000000000000476.