Remember when six (or even eight) small meals throughout the day was the golden standard for a proper diet?
In college, I was all in. I would spend half an hour each morning prepping tupperware with small portions to graze on throughout the day. I thought I was doing everything right – some oatmeal and eggs in the morning, piece of fruit and protein shake mid-morning, chicken and rice for lunch, etc. I felt like I was constantly eating!
This idea of grazing throughout the day (we’ll call it “nutrient timing”) seemed to make sense on paper. For one, it seemed like an obvious way to curb cravings and prevent binging on those donuts in the copy room.
One other supposed benefit of spreading out your meals was to increase metabolism. If we think of metabolism as this inner “fire” of sorts, burning fuel to provide energy, the more we stoke the fire, the hotter it’ll get right? If we eat smaller meals throughout the day, the thinking went, we’ll “rev up” our metabolism so we burn more calories at all times.
It turns out that smaller meals throughout the day might not have as big of an impact as one would hope. The Journal of the International Society of Sports Nutrition even published a study suggesting that nutrient timing is largely a matter of personal preference and offers little benefit for metabolism and weight loss.
So, if you don’t have to eat every few hours for optimal health, what if we explored the other side of the spectrum? Instead of eating throughout the day, what if we (gasp) skipped breakfast and ate fewer meals in total?
The Upsides of Skipping Breakfast
If you break down the word “breakfast,” you come up with a literally meaning – break fast. Normally, we eat dinner around 6 or 7pm, maybe have a snack before bed, and then fast for 10-12 hours until the next morning. At breakfast, we’re literally breaking a period of fasting.
For years, along with the idea that smaller meals throughout the day were necessary for optimal health, breakfast was critical to start your day on the right foot.
Then, a new way of eating, one where you skipped breakfast (and maybe even lunch) started making waves. Called intermittent fasting or IF for short, this new way of eating promised more sustained energy, better body composition, and improved bio-markers like insulin and growth hormone.
There are dozens of different IF protocols out in the wild, but here are some of the more popular ones:
- Fast for 24 hours 1-2 times per week (Popularized by the book Eat Stop Eat)
- 16 hours of fasting per day/8 hours of eating (So you might eat between 12pm and 8pm)
- 20 hours of fasting per day/4 hours of eating (You might only eat dinner or two small meals between 4pm and 8pm)
Intermittent Fasting in a Nutshell
The gist of IF is pretty simple – pick an eating method (the most popular ones are listed above). During fasting periods, you can have water, coffee, and some bone broth. Other than that, you’re waiting until your “feasting” periods to eat. Simple as that.
Let’s talk science for a second. What are the supposed benefits of IF?
First, let’s not get IF confused with calorie restriction. Even though you’re limiting your feeding window throughout the day, the goal with IF is still to meet all of your nutrient requirements (just in less time). This isn’t some kind of starvation diet (those aren’t healthy, and they don’t work long-term).
Another thing to realize: Humans have been fasting for a long time, whether that’s for religious reasons, during food scarcities, or just overnight as we mentioned before. IF just makes it a bit more intentional.
Okay – the proposed benefits. I’m going to share some conclusions from Precision Nutrition; they wrote a (free) book on the topic that’s worth checking out if you’re interested:
Suggested Benefits of Intermittent Fasting
via Precision Nutrition
- blood lipids (including decreased triglycerides and LDL cholesterol)
- blood pressure (perhaps through changes in sympathetic/parasympathetic activity)
- markers of inflammation (including CRP<, IL-6, TNF, BDNF, and more)
- oxidative stress (using markers of protein, lipid, and DNA damage)
- risk of cancer (through a host of proposed mechanisms; we’ll save them for another review)
- cellular turnover and repair (called autophagocytosis)
- fat burning (increase in fatty acid oxidation later in the fast)
- growth hormone release later in the fast (hormonally mediated)
- metabolic rate later in the fast (stimulated by epinephrine and norepinephrine release)
- appetite control (perhaps through changes in PPY and ghrelin)
- blood sugar control (by lowering blood glucose and increasing insulin sensitivity)
- cardiovascular function (by offering protection against ischemic injury to the heart)
- effectiveness of chemotherapy (by allowing for higher doses more frequently)
- neurogenesis and neuronal plasticity (by offering protection against neurotoxins)
Okay, okay – you’re probably thinking that this sounds like a miracle cure that apparently improves every aspect of your life. It’s worth noting that (as is typical with nutrition) your mileage may vary. Studies are still exploring the full ramifications of IF. When in doubt or if you decide to try this, use the ultimate scientific test – “How do you feel?” Always look at these things with a critical eye and really figure out if it makes sense for you and your life.
Obviously, this wasn’t an exhaustive dive into intermittent fasting and the various protocols available. I mostly just wanted to introduce the concept so you can explore further on your own if you want. More than a specific way of eating, I wanted to break some long held notions about nutrition (that you have to eat small meals throughout the day) and encourage you to find what works for you. I happen to really love IF, especially in specific circumstances. For example, if I’m traveling and can’t find a healthy meal, I’ll just fast until I get to my destination. I also find I have better mental clarity in the mornings when I fast.
If you’re interested in diving deeper on the subject, I recommend starting with this free ebook by Precision Nutrition. It provides a great overview of IF and a balanced approach of weighing benefits with the unknown.
Warning just in case: I’m not a doctor, and I don’t play one on the internet. I do try to reference sound science. Prior to trying any diet, it’s definitely worth chatting with a medical professional. This blog post was meant to introduce a concept and give an overview of different way of eating – not suggest it’s the way of eating for everyone. Be sensible.