Some time between 6.30 and 9.30 p.m., Twitter CEO Jack Dorsey eats his only meal of the day, one that typically includes "fish, chicken, or steak with a salad, spinach, asparagus or Brussels sprouts." Dorsey says his one meal a day (OMAD) eating regimen lets him "feel so much more focused."

What Dorsey -- and many other entrepreneurs -- does is a hyper version of intermittent fasting, an increasingly popular eating regimen that many people say helps them burn more fat, reduce inflammation, and improve mental acuity. 

If you want to try intermittent fasting -- here's a beginner's guide to intermittent fasting -- there's an app that makes the process easier and adds a social component. (Think Strava for intermittent fasting.)

The LIFE Fasting Tracker is an app created by LifeOmic, a startup founded by serial entrepreneur Dr. Don Brown that builds cloud and mobile technologies to drive innovation in precision health and improve patient outcomes.

Oddly enough, the app was never intended for widespread adoption. Dr. Brown wanted to build a mobile app to test the connectivity and scalability of the LifeOmic platform, and since he was passionate about intermittent fasting decided to create a free fasting app that a few hundred people might use that would allow the company to test their systems while "doing a little bit of good in the world." 

But without any promotion or advertising, the app took off -- and now over 300,000 people use it to track their fasting habits, share progress, and encourage friends.

I talked with Dr. Brown about the science behind intermittent fasting, starting a healthcare company... and how you can give intermittent fasting a try.

Let's talk a little about the science behind intermittent fasting.

Research shows that, while it sounds odd, animals that are kept at a low calorie level over their lifetimes will live longer and have a lower chronic disease burden -- especially the diseases people typically get as they grow older. 

I was intrigued by the notion but knew in my heart I was never going to be able to live on 60 percent of my normal amount of calories. (Laughs.) Living on 1,200 calories a day? Ugh.  

Most people are the same way. We love the things we love. Since I'm from Kentucky, I have a fondness for biscuits and gravy. (Laughs.)

The benefits are obvious (obesity, Type 2 diabetes, etc.) but it's really hard to maintain a relatively low calorie diet for years. 

Absolutely. But then I read a paper by Walter Longo at USC that showed you don't have to permanently restrict your calories to get the benefits of caloric restriction. You could just do it periodically.

That's the basis of ketosis: Restrict calories long enough to let your liver use up all its glycogen and switch over into burning fat.

I thought it might be a fad, but after going on a tear and reading all the research I realized the concept is fundamental. There's a cellular basis for the mechanism of intermittent fasting.

Thousands of years ago our ancestors didn't have refrigerators and bags of Doritos and a way to consume calories whenever they wanted. They had to find a source of food. Sometimes that meant waiting for days before eating again. 

That's how we were designed. That's what we were built for. It turns out periods of fasting causes us to improve our brain activity, secrete chemicals that spur the formation of new neurons... and helps avoid us dying from "over nutrition." Over-nutrition increases the risk of obesity, Type 2 diabetes, cancer...

"Over-nutrition" sounds odd, but it makes sense. We only need what we need. The key is to restrict calories without malnutrition.

Based on all the research, we've really started to understand intermittent fasting. And it's taken off. 

But people still react negatively. They think you're practicing an eating disorder. Or making yourself anorexic.

That makes me want to tear my hair out. Obesity and Type 2 diabetes are widespread problems and are in large part totally preventable. Adopt a sane way of eating that drops insulin levels, doesn't lead to an eating disorder, makes you appreciate food more... after 16 hours you don't want Doritos. You want something good. You eat more slowly, you savor every bite... it's paradoxical to some degree, but intermittent fasting creates a healthier relationship with food.

Unlike a lot of diets, intermittent is simple. It doesn't cost more money. Anyone can try it. And unless you take it to incredible extremes, very few people will hurt themselves doing it. 

The evolutionary aspect of it is really interesting. We forget that constant access to food, at least for some, is a fairly new phenomenon.

We're cyclical machines. Our species, like lots of other species, have spent millions of years on a planet where we get 12 hours of sunshine a day. Our systems have evolved over this immense period for that world.

So in our evolutionary past, we ate during the daytime. That's when we could hunt and could gather. Then at night we found shelter and worried about staying warm and not getting eaten ourselves. (Laughs.)

That's the environment we evolved for. And it gave our stomachs a chance to rest, gave our insulin levels time to drop, and kicked us into this recycling mode that we call autophagy, which is the systematic degradation and recycling of cellular components. as we realize the chronic effects of aging are gunky proteins that come up over time.

During times of privation, a little bit of "starvation," our bodies go into high efficiency recycling mode. That leads to recycling held proteins that might lead to some of the nasty diseases of aging.

Talk about creating the app.

After selling a previous company I started LifeOmic. We built a cloud system to aggregate data about cancer patients and use machine learning to analyze that data. 

But we also wanted to tie patients into it and help them take more control over their care. Since I found I was serving as an evangelist for intermittent fasting (laughs), I thought it would make for a good test bed. 

So we built the app to let people see their own status and interact with others in social circles they create to share information, participate with friends and family... and now we have tens of thousands of circles all over the world. 

Say a reader is interested in intermittent fasting but doesn't know where to start. Advice?

Keep it simple. The best way to start is to enjoy your dinner, don't change anything that you eat... but then don't eat again until breakfast. Drink water but don't take in any more calories. Give your body a break from dinner until breakfast.

For most people that will be a period of about 12 hours. That's a 12-hour fast. That's where it all starts.

I know what you're thinking: "Wait. That's it?" Yes. There's this tendency to think you have to try an extreme solution for something to work... but that's simply not the case.

Keep in mind that eating before bedtime is especially bad for you.

So that's the first step: A 12-hour fast from dinner to breakfast.

And then you can slowly increase the duration.

The next step is to eat breakfast a little later. Maybe at 8 or 9 a.m., turning a 12-hour fast into a 13- or 14-hour fast. 

And that can be the end point for most people.

Doing a 14-ish hour fast, several days a week, will kick your body into ketosis and force you into a metabolic switch from sugar burning to fast burning. Do that a few times a week... and for the vast majority of peoplem that's all you need to do.

You'll lose a little weight over time, and it's a sustainable weight loss. Tested glucose levels will come down, serum insulin levels will come down... insulin is like a go switch to every cell, including cancer.

So it's really important to reduce insulin levels.

But if you want to go farther, the next step is to once in a while not eat breakfast. Even though your mother told you differently, you won't die. (Laughs.)

Breakfast is not the most important meal of the day, and there's nothing wrong with once in a while not having breakfast.

Do that and once in a while you'll get in an 18 hour fast. That's not radical and definitely not dangerous. And then maybe one day you try skipping lunch and have a nice, big, healthy dinner.

Now we're into Jack Dorsey land.

(Laughs.) The thing is, you won't die even if you do that most days of the week. One meal a day is a perfectly acceptable approach as long as you eat the variety of foods you need and don't deprive yourself of the baseline amount of calories.

The first time I did a 24-hour fast, I felt like I had climbed Mt. Everest. (Laughs.)

But after I did it a few times, I realized it was embarrassingly easy.

And keep in mind that throughout history, people have fasted for a day or two out of necessity. They weren't always guaranteed breakfast and lunch.

That's the neat thing about intermittent fasting. Once you start practicing it, it gets really easy. And sustainable.

Which is the real key to making lasting, positive changes.