The Perfect Intermittent Fasting Ratio for the Most Weight Loss

Dr. Eric Berg 08/31/2023

You’ve heard about the impressive weight loss results from intermittent fasting. You know you’re supposed to go a certain number of hours without eating, and the pounds will come off. It seems very simple.

Best of all? No counting calories or sticking to some weird diet.

But what you want to know is how many hours of fasting is ideal for optimal fat burning. What's the best eating pattern to get the results you want? How can you set a realistic eating schedule for yourself without wrecking your metabolic rate?

You’re not alone.

Let’s dive in.

In this Article: -

How Many Hours To Eat And Not Eat?
How To Successfully Go Longer Between Meals
Here’s What I Recommend If You Have A Lot Of Weight To Lose
One of the Fasting’s Incredible Benefits
One Step You Can Take To Further Boost Fasting’s Benefits
Putting It All Together

How Many Hours To Eat And Not Eat?

I get this question a lot:

At what ratio should I do fasting - in other words, not eating - with eating, to produce the most weight loss?

A photo of a clock on a plate with fork and knife

Research shows that you’re going to mobilize the most fat and lower the most Fat Storing Hormone right around 18 to 24 hours of fasting in a daily cycle.

Let’s look at this more closely.

If you eat at 12 pm and then again at 6 pm, that gives you a 6-hour window of eating.

Then, you’ll fast until noon the next day, giving you 18 total hours of fasting.

Now, consider another scenario.

Let’s say you eat one meal at noon, and then fast until noon the next day. That gives you a 23-hour fasting cycle.

You can choose either pattern, or land somewhere in between, and be in the optimal range.

Many of you are doing intermittent fasting and eating one meal a day, known as OMAD. In fact, nearly all of the people I’ve interviewed on Skype are eating just one meal a day, and are doing very well.

But if you’re new to intermittent fasting, I encourage you to ease into it and let your body adapt.

How To Successfully Go Longer Between Meals

Here’s how I recommend you adapt to intermittent fasting with a time-restricted eating window.

First, go to three meals per day and eliminate all snacking. For some people, eliminating snacks is the most difficult challenge. People snack for all kinds of reasons that don’t have anything to do with hunger.

You snack because you’re upset. Or bored. Or even happy: celebrate with a snack!

But if you want to lose weight and be successful with intermittent fasting, cut out the snacks first.

Once you feel good with just three meals a day, move on to the next step. Push your breakfast later into the morning until eventually, you stop eating it altogether. Make lunch your first meal of the day.

My Number One Rule Of Fasting

You’ll find that over time, you’ll naturally not feel hungry first thing in the morning. So, don’t eat in the morning if you’re not hungry! That’s actually my number one rule of fasting:

Don’t eat unless you’re hungry!

At Two Meals A Day, You Have A Choice

When you stop eating breakfast, congratulations! You know you’re successfully adapting to fasting. You should be losing weight, and feeling good.

And sow that you’re eating two meals per day, you have a choice.

You could stay with eating two meals, one at noon and one at 6 pm.

But if you’d like to transition to longer fasting with a narrower eating window, you will push your lunchtime out later and your dinnertime earlier. 12 pm becomes 1pm, 6pm becomes 5pm. Your eating window is now 4 hours, giving you 20 hours of fasting. That’s a great sweet spot to hit!

Then, if you want to transition completely to OMAD, you simply continue narrowing your eating window.

Although I know many people who are successful at one meal per day, there are certain situations for which I recommend something different.

Let me explain.

Here’s What I Recommend If You Have A Lot Of Weight To Lose

If you have a lot of weight to lose, I recommend staying in that 20 hour sweet spot. As well, if you have significant Fat Storing Hormone resistance - a prediabetic state - or if you’re in full-blown Type 2 diabetes, your body has suffered a fair amount of damage.

Thus I want you to ease into fasting as I’ve described, not only to make it as easy for yourself as you can, but to give your body time to get its healing process underway.

If you’ve already lost weight, reached your goal, and don’t have a history of disordered blood sugars, you should do fine staying in a 12 to 16 hour fasting cycle.

And here’s another incredible benefit of fasting that awaits you.

One Of Fasting’s Incredible Benefits

Even if you don’t want to lose more weight, you may still want to stay in the 18-24 hour fasting window.

The reason?

You’ll stimulate what’s called autophagy

The word autophagy in white on a blue background

Autophagy is like turning your cells into self-cleaning ovens. When autophagy is triggered by fasting, your cells will clean up damaged parts, old viruses and fungi, and recycle them into fatty acids and protein your body can use.

Intermittent fasting can increase autophagy by 5 times more than if you didn’t fast. And when you consider that autophagy has exciting implications for anti-aging (because it creates younger cells); it removes toxic proteins that are associated with Parkinson’s and Alzheimer’s; and, it may also prevent or treat cancer - well, who wouldn’t want to ignite as high a level of autophagy as possible?

Compare this with someone with diabetes, whose cells by comparison will be very dirty. The self-cleaning process is inhibited, allowing waste products to accumulate within the cells. When you have diabetes, there is significant damage to the eyes, kidneys, and heart.

In other words, if you’re diabetic or pre-diabetic, you want to stimulate autophagy to give yourself the best possible chance at repairing your dysfunctional cells.

One point about diabetics: if someone with diabetes was to consume B vitamins from nutritional yeast, they would have less damage to their mitochondria (the energy powerhouses of the cells), and less waste buildup.

One Step You Can Take To Further Boost Fasting’s Benefits

For those of you who want to transition to one-meal-a-day, you can increase the effects of fasting by adding in what’s called high intensity interval training, or HIIT. in your fasting window, either before or after your eating window.

I know of people who are working out 6 days a week. I recommend twice a week, preferably with a personal trainer. Hitting two hard HIIT workouts twice a week, combined with fasting, and walking the other days of the week, would be optimal.

When you add HIIT to fasting, you’re really taking your weight loss and health journey to the next level.

high intensity interval training written on a chalkboard with a dumbell and apple next to it

You’ll spike human growth hormone, something you had in abundance as a growing child, but which usually wanes as you age. Growth hormone can help build healthy tissue, and repair damaged cells. It’s no wonder some people spend thousands of dollars to have it injected into their bodies.

But you don’t need to take such drastic action if you fast and do HIIT while fasting.

The Finishing Touches

The finishing touches that will really bring all your efforts together beautifully is to make sure you get enough sleep. This also means to be careful not to overtrain, and be sure to give yourself time to recover from workouts.

Finally, keep your vegetable intake high, and your carbohydrate intake below 20 grams per day, as you would when you’re on my Healthy Keto^TM diet. Yes, vegetables have carbs, but don’t include their carb count in the 20 grams of your daily allotment.