When it first came out to the public, the Leangains Protocol raised a lot of eyebrows. Also known as the 16:8 intermittent fasting and workout system, Leangains was dismissed as just another diet fad.

However, after a number of scientific studies proved its effectiveness, Leangains became the must-do diet of the day. Sadly, just like most popular diets, the bandwagon blew up Leangains out of proportion. So-called diet gurus called it the new miracle diet. They emphasized results but without being clear on the work required to get there.

This guide to the 16:8 Leangains Protocol aims to shed light on what this diet is really all about. More importantly, we aim to outline the work Leangains requires and the expected results.

Overview and history of the 16:8 Leangains Protocol

Small but frequent meals are necessary for weight loss. That’s the popular belief among weight loss gurus before the 16:8 Leangains Protocol came out. Grazing throughout the day is thought to keep the metabolic rate up. It’s also considered helpful in oxidizing and breaking down fat more quickly.

The problem with small but frequent meals daily is your life tends to center around your diet. This means you spend a great deal of time preparing and obsessing over the healthiness of your food. You also become inclined to skip on social obligations where you’d have to break your diet.

For some people, grazing still leaves them hungry despite the frequency of their meals. Research also came out later casting doubts on whether grazing is even effective for weight loss.

This is a problem that Swedish nutritionist and personal trainer Martin Berkhan experienced, personally and with his clients.

So in 2006, he came up with the Leangains Protocol. At its core, Leangains is about fasting for 16 hours. This fast is then broken with three meals within an eating window of eight hours. This fasting and eating routine is then complemented by varying intensities of workouts.

Main purpose and goal of the 16:8 Leangains Protocol

The primary purpose of the 16:8 Leangains Protocol is to trigger the body’s natural ability to burn fat. With intermittent fasting and regular workouts, the protocol is designed to force the body to use its stored fat for energy.

According to advocates of intermittent fasting, the body essentially exists in two states. One is the fed state, while the other is the fasted state. As its name suggests, the fed state happens when we have just eaten.

The body is busy breaking down food to its component parts and digesting them with the help of insulin. Insulin transforms food into glucose that the body can readily use for fuel. The food energy that the body can’t use gets stored in the liver as glycogen for later use. If the body doesn’t use up this stored glycogen, the liver converts it into fat to make room for new glycogen.

On the other hand, when the body is in the fasted state, it uses up available glucose. Without any food to convert to glucose, insulin levels go down. Once it finally runs out of glucose, the body is forced to use the stored glycogen in the liver for fuel. And when that glycogen is out, the body then turns to its stored fat for energy.

In an interview with blogger and fitness coach Leigh Peele, Martin Berkhan stated that it takes six to seven hours for the body to fully digest a regular-sized meal. Then it takes 28 hours to completely deplete the glycogen in the liver without any strenuous activity. With strenuous activity, though, the body can use up its liver glycogen much more quickly.

So, with the Leangains Protocol, you can pursue two goals. One is to lose weight by burning off unwanted fat. The other is to gain weight, build muscle, and burn off fat without losing muscle mass.

Who is the 16:8 Leangains Protocol ideal for?

Anyone who wants to lose fat can go on the 16:8 Leangains Protocol. It’s even better if you’re willing to spend an hour working out before your first meal for five days a week.

However, women who are trying to get pregnant should reconsider going on the Leangains Protocol. There is very little literature on the effects of intermittent fasting on women in general. Studies using female rodents, on the other hand, have shown that the subjects stop ovulating and menstruating when put on intermittent fasting.

There are also signs that the subjects become less sensitive to insulin and glucose. Women who are breastfeeding should also think twice about intermittent fasting. Their body needs extra calories to feed their babies.

Intermittent fasting may help in preventing or even reversing type-2 diabetes. Nonetheless, if you’re diabetic, you must consult your doctor before getting started on Leangains.

Is the 16:8 Leangains Protocol easy to do?

The 16:8 Leangains Protocol is easy to implement. But it does take a lot of adjustment at first. One area of adjustment involves having to skip breakfast and push back mealtimes. The other has to do with your behavior and relationship towards food.

Most of us are conditioned to eat breakfast within minutes of waking up. With the Leangains Protocol, you are recommended to skip this meal altogether as part of your 16-hour fast. This can put you off-kilter if you’re a regular breakfast-eater.

You’re expected to experience hunger pangs, headaches, cravings, and general weakness of the body upon starting this protocol. You may be irritable, prone to anger, and unable to focus as well. However, the body usually adapts to the new eating pattern within two weeks.

Additionally, you’re recommended to do one-hour workouts of varying intensity five days a week. If you’re mostly sedentary, your body may resist this change in your routine. But these workouts are necessary to deplete your liver glycogen more quickly and trigger the body’s fat-burning ability.

You are given the freedom to choose when to do your workout, but it’s strongly suggested that you do so an hour before your first big meal of the day. And don’t worry – as long as you don’t overdo it and you are in control of your food intake, you don’t need to worry about losing muscle while doing fasted workouts.

leangains fasted cardio exercise

Fasted exercise early in the morning (preferably at high intensity) is a staple of the Leangains Protocol.

Foods that are part of the 16:8 Leangains Protocol

The 16:8 Leangains Protocol doesn’t impose any food restrictions. In fact, Martin Berkhan has bragged about being a cheesecake master and staying lean while drinking alcohol.

What Berkhan recommends is maintaining a healthy diet. By healthy diet, he means a diet rich in lean proteins and whole, unprocessed foods. Berkhan puts a great deal of importance on lean proteins. That’s because proteins make you feel full more quickly and for much longer.

The thermic effect of food is also higher with protein. Thus, you get to burn more calories while digesting protein. Protein is also necessary for optimal muscle retention while burning fat.

Rather than food restrictions, the Leangains Protocol focuses more on when you should eat. Berkhan recommends scheduling the 16-hour fast to occur overnight and in the early hours of the morning. This means skipping late-night meals, midnight snacks, breakfast, and mid-morning snacks.

The eight-hour eating window ideally begins at noon and ends at 8:00 PM. You can eat three meals within your eating window.

Why this schedule? The 16-hour overnight fast is enough time to deplete most of the glycogen in the liver. It also increases insulin sensitivity.

The eight-hour eating window, on the other hand, makes sense socially. People do lunches at work with colleagues and dinner with family. Berkhan has also debunked the myth that breakfast is not the most important meal of the day. Moreover, there are studies showing that eating or skipping breakfast has no effect on weight loss.

Calorie intake is another factor that the Leangains Protocol focuses on. While intermittent fasting is an important component of Leangains, it does not go for drastic calorie restriction.

Berkhan stresses the importance of being conscious of your calorie intake. You need to feed yourself sufficiently on workout days and eat a little less on rest days.

Foods that are to be avoided on the 16:8 Leangains Protocol

As mentioned, Martin Berkhan does not impose food restrictions on his Leangains Protocol. However, he does have strong words for nuts, dried fruits, and smoothies.

While most diet gurus advocate eating nuts and dried fruit, Berkhan recommends ditching them altogether. He claims eating fish is more beneficial than nuts and dried fruits.

According to Berkhan, nuts contain more calories than chocolate and are not filling at all. Dried fruits, on the other hand, are just lumps of sugar with fiber. Nuts and dried fruits are just a waste of calories. The same goes for protein bars, which Berkhan calls glamorized candy.

Berkhan also calls shakes, power smoothies, and other liquid calories as a waste of calories. They are convenient, but they don’t help with satiety. They also cause insulin spikes and trigger hunger. He says it’s best to eat your calories through a complete meal than drink them as smoothies.

How effective is the 16:8 Leangains Protocol overall?

Anecdotal evidence presented by Martin Berkhan shows that the Leangains Protocol is effective in gaining muscle mass while burning off fat. The anecdotal evidence comes from Berkhan’s personal experiences as well as from his clients’.

But is it effective from a scientific standpoint? According to a review of literature from the University of Aberdeen in Scotland, intermittent fasting may be an effective method for losing weight. Intermittent fasting shows promise because it’s easy to follow and it changes behavior towards hunger rather than simply restricting calorie intake.

On the other hand, another review of literature claims that Leangains and similar intermittent fasting systems have no scientific basis. The paper states that exercising in a fasted state, as advocated in Leangains, does not burn fat effectively. It can also result in loss of muscle mass and potentially detrimental to athletes.

Potential mistakes to avoid on the 16:8 Leangains Protocol

Not fully understanding what the 16:8 Leangains Protocol can lead to the following mistakes:

  1. Not eating enough. Intermittent fasting under the Leangains Protocol means pushing back your eating schedule later in the day. Even so, you must stick to your recommended daily calorie intake. Not eating enough while fasting periodically can slow down metabolism, cause muscle mass loss, and slow down fat burning.
  1. Not paying attention to what you eat. There are no food restrictions in the Leangains Protocol. As mentioned, even Martin Berkhan indulges in cheesecake, ice cream, and alcohol every once in a while. Still, this is not a free pass to eating whatever the heck you want during your eating window. You still have to limit your intake of simple carbs and sugars.
  1. Not doing enough intensity workouts. While cardio training is a great workout, you shouldn’t rely exclusively on cardio training to help you shred off the fat. Otherwise, you will force your body to break down your muscle tissues for protein to fuel your cardio workouts. Instead, you should balance your cardio training with high-intensity strength training. Doing so will effectively burn off your fats without breaking down your muscle tissues.
  1. Obsessing over your meals. Martin Berkhan designed the Leangains Protocol because he got tired of having his diet take over his life. You shouldn’t let yours do the same. If you have to eat pizza or ice cream outside your eating window, just eat it. Don’t stress over it and just get back on track the following day. If you have to attend a social function that involves eating, go ahead and enjoy yourself. So you wouldn’t go off the rails, eat your full allotment of protein for the day before you go.

How healthy is the 16:8 Leangains Protocol?

The 16:8 Leangains Protocol is more of a diet schedule than a diet itself. Since it advocates eating lean proteins and whole, unprocessed foods and complementing meals with workouts, Leangains is as healthy as it gets when it comes to intermittent fasting diets.

You can even modify the protocol according to your preferences. But if you have health issues that could be affected by intermittent fasting, it’s best that you consult your doctor first.

Our 16:8 Leangains Protocol diet review conclusion

One thing that we always look for when examining a diet is whether or not it has any real-life results and applicability. And while Martin Berkhan’s popular Leangains diet has had mixed reviews when it comes to scientific studies, there is no question that a lot of people have been able to use it to get extremely lean and fit.

Want proof? There’s plenty of testimonials and success stories on Berkhan’s official Leangains website. As long as you stay disciplined when it comes to your meal timing and ensure that you get adequate nutrition and exercise, the 16:8 Leangains Protocol will definitely not disappoint if you are looking to get maximally lean in as little as a few weeks.


What’s your biggest challenge when it comes to reaching your healthy eating and weight loss goals? For most people, it’s the ability to accurately map out exactly what they need to eat, and when. It’s even tougher to do this consistently on a daily basis. We recommend this meal planning tool, which helps you do all that and more.

From calculating your daily intake needs to generating automated meal plans and grocery lists, this all-in-one meal planner will help you accelerate fat loss and muscle gain while cutting the waste out of your diet. Try it out and let us know how it helped you get fitter and healthier!