The Science Behind Intermittent Fasting (14 Studies) | Nutritional Science Explained

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▹ MY BODY RECOMPOSITION SCIENCE VIDEO →

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IN THIS VIDEO ▹

SOURCES:

This paper was extremely valuable in making this video. The work Dr. Bojan did here is incredible and I'd strongly recommend reading it in full for a deeper understanding of IF:

I also drew heavily from Alan Aragon's Research Review. You can subscribe here and gain access to all issues:

The Lean Gains Guide

Fasting Benefits (Rat Studies)

Two Obese Studies Showing Positive Health Effects

Two Lean Studies Showing Less Impressive Results

IF and Hunger:

Huge Systematic Review (40 studies)

Liver Glycogen and Muscle Loss

Metabolism, Thermic Effect of Food and Meal Frequency

MPS Study Favouring 4 Meals:

IF and Disordered Eating

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MUSIC
NAUUDA - who likes liquorice anyways
Blue Wednesday - Passing the Torch

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This video was edited by Rashaun and I (it took us about 30 hours to make this video not including research and writing)

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MY HEIGHT
I'm 5'5

[JeffNippard]

Ok a few quick things...




As always (of late anyway) I've included a full annotated list of references organized by order of appearance in the description box.

Hope you enjoyed the video and I’ll see you guys again soon. Peace!

[mrspark]

i've been intermittent fasting for around 6 months now. i've lost around 15kg and i'm the strongest i have ever been, i haven't noticed any decline in strength only a steady increase.

[ckoen]

As far as IF goes, I started in January of this year at 209lbs and am now at 183lbs in the first week of may. That’s 26lbs! This is the only diet I have been able to adhere too so far and I’m loving it! Changing my mindset to “ this is how I eat” from “I’m on a diet” was probably the single greatest factor in making me stick with it.

[RobLipsett]

Quality info and editing as always man. Easy watching!

[bryanpacheco]

Intermittent fasting is simply a tool, not a diet. Skip breakfast and start your day of eating at about 12, 1, even 2. This will help you managing your calories when cutting.

[davidhensel]

I feel like so many people freak out about the thought of a 16 hour fast, but then forget that an 8 hour eating window would be breakfast at 9am, lunch at 1pm, and dinner at 5pm. Boom, you're intermittent fasting.

[drewkocak]

The best diet is the one to which you can adhere. Yesss 💯💯

[Doccplayz]

I’ve been practicing IF for about a year and a half now and it makes staying lean so easy. First time I’ve ever been able to get noticeable abs and was just a month or two after starting IF. After the first couple weeks you don’t even realize you’re fasting, you’re body gets so used to it. It’s also possible to bulk on IF as well as long as you’re in a caloric surplus and still remain lean year around. I would 110% recommend it to people.

[StephanieButtermore]

Editing getter better and better babe... HOT FIRE 🔥🔥🔥

[jonathanfeigert]

I started intermittent fasting about 5 months ago. Can't say I've noticed any change in my ability to gain muscle or lose fat, but I definitely find that it blunts your appetite on the mornings and is overall more satisfying at the end of the day.

[abbypollock]

Great vid Jeff 🙌 Ive been practicing IF for nearly 2 years now. Def agree with the appetite blunting effects with the caveat that there’s an adjustment period lol.

[davewalton]

HI Jeff. I have experimented with IF and here's what I found. At first it was tough, but after a few weeks I found that my appetite was definitely falling and rarely felt any cravings like I did prior. I was working with only an one hour window at first with just one large meal a day. My concentration started to improve a great deal also. After a few months, IF was starting to lose its effectiveness so I now cycle it, and just do it from time-to-time, including a 36 hour fast once a month. In sum: I have found it a very useful technique for weight loss, and will continue to use it as just one tool in the arsenal. I now predominately do it on training days (Mon, Tues, Thurs, Fri) and have my first meal about 2pm. But I do find it much better when I switch things up a bit and make last minute changes. Just like with keeping the muscles off-guard by using different exercises, it turns out that the diet also works worth the same method by keeping the body guessing on what's coming next. Some days I will just wake up and decide I'll do a 24 hour fast and just do it.

PS: I'm 45 years old and was 325 pounds. I suspect it works best with obese people.

[andrewreeves]

Love the videos Jeff!

Intermittent fasting was introduced to me in July of 2017 when I weighed around 235 lbs. Using IF for 4 months I dropped 60 lbs and hit my lowest weight of 175 lbs. During this time I did start to focus more on macros and eating better, but having fewer, big, and fulfilling meals made me feel like I was eating a lot more than I actually was, which was able to put me in a bigger caloric deficit. I did notice HUGE increases of energy and moral positivity over the first few months, but soon realized that it decreased once I started getting to a lower body weight. I realized now that my caloric intake may have been to low, and although I lost my fat relatively quickly... I started to plateau and began to lose lean muscle mass. To note: I did absolutely no resistance training during these 4 months, only cardio(big mistake).

If there is one take away from doing IF is that it's a great tool when used properly. It can be great for initial fat loss, but without a balanced training program and putting yourself in a reasonable caloric deficit, it can be pretty harmful and produce the complete opposite results. Once you start to decrease your caloric intake too much and your body accustoms, it becomes unsustainable. You start to feel miserable, and in most cases your weight begins to plateau due to muscle loss rather than fat loss, thus decreasing performance and gainzz.

I've been getting into the science and research behind how the body works and using that knowledge to transform my body after I took a step back and restarted my metabolic rate. It's crazy that this journey started off by just trying to lose weight due to discomfort and self doubt into building and structuring a body I never thought possible. So thank you for taking the time to create such informative videos providing us with the information and facts to learn and incorporate into our own life. You are an inspiration and I wish you the best my friend.

[skabumble]

I think we need Broscience Jeff in every video from now on

[shooker]

Who is your editor? Because honestly, aside from all of the useful information that can be gained from these videos ; the editing makes that much easier to consume all of this information.

Edit : I just read the description ; Rashaun you are the man!

[dxa]

Been watching your videos for some time. For me, IF has been a great thing. I'm knocking on the door to 50, and needed something to shed weight. I don't think you've ever had a weight problem, but I was at 285 lbs Feb of 2018 when I started IF. I started with skipping breakfast ... then pushing lunch back to 1pm ... then 2pm ... then 3pm ... and before I knew it I was 20 hours fasting and 4 hours eating. It was tough the first week, but once your body gets used to the new eating window ... you adapt. I then started with walking 10K steps a day. I moved to running ... added in weight lifting ... and then learned how to do HIIT. By August, I surprised myself. I was down to 192 lbs and on my birthday ran a 5K in under 28 minutes, which I couldn't believe. I do this M-F and then eat within reason on Saturday and Sunday. So, I sing the praises of IF, because I haven't felt this good in a decade or so. I am off High blood pressure medicine, and looking to see if I can actually get a six pack to show through. That part is tough at my age, but it's fun trying. For me, with the 4 hour window, it greatly helped me to reduce my caloric intake ... increased my mental state/clarity ... gave me a boost of energy. Great videos for reference, appreciate it.

[Jiezel]

I am on my 2nd month of IF and recently rejoined the gym after 1.5 years following an injury, I have some experience in bodybuilding and now experiencing this new adventure with IF and building muscle quite surprising. I fast 20 hours and eat only between 7.00pm and 10pm. I go to the gym at around 5.30pm, so you can imagine I have been fasting almost 19 hours prior to start my training. Here is the thing, I feel so energetic, no need for pre-workout, and I'm lifting really well. I’ve lost body fat and starting to see the muscle growth. This is not the best part, my mental health has been so good since. I can focus a LOT more in my work, I have improved my level of concentration and feel happier in general! This is quite impressive to me!
However, I have also added 2g (combined EPA and DHA) of fish oil and 5000IU of Vitamin D3 together in my diet. So, I don't know what share of IF against those 2 supplements are contributing to my significant improved overall well-being, but I'm enjoying it a lot!

[conodeen]

It’s been four years since this video so would like to see if there’s any updates to the scientific understanding.
I’ve been on one-meal-a-day for close to two years now. Seem to be doing ok. Stopped losing fat a while back (so I guess my body adjusted to the lower calories) but other than that I’m doing good.

[nihal]

I'm 17 and I used IF effectively to lose almost 30kg while also having an active lifestyle. I planned all my meals with adequate macros and micros needed for my body, so even during my eating window, I made sure whatever I was eating was purely healthy. Also, I haven't seen any decrease in my strength. In fact, I became better at my workouts than before.

[mofo]

Me during Ramadan, great video Jeff 👌 still waiting for a full body training plan from you