Leangains: A Simple, Science-Based Guide

Leangains is a style of intermittent fasting created by Martin Berkhan, who is a personal trainer and a nutritionist. Leangains is a daily routine centered around structured eating, fasting and resistance training. In this article, you’re going to learn all about the leangains diet.

We’re going to cover the pros and cons of leangains, and explain how it differs from other styles of intermittent fasting. Lastly, we’ll be walking you through how you can calculate your leangains macros accurately for the best results.

What Is Leangains?

Leangains, otherwise known as 16/8 intermittent fasting, involves eating all of your calories during an 8 hour period and fasting for 16 hours. The basic fundamentals of any intermittent fasting routine revolve around a period of not eating (the fasted state) and eating (the fed state).

Feeding window: During the 8-hour feeding window you consume all of your meals for the day.

Fasting window: During the 16 hour fasted state, glycogen in the liver is depleted. When liver glycogen is depleted, the body enters a state of ketosis (fat burning). As the body burns fat, it produces molecules called ketones. The longer you stay in a fasted state, the deeper into ketosis you get, and the more fat you burn (1, 2).

While many other intermittent fasting protocols focus on regular, small meals during the fed state, the leangains diet advises 3 larger meals. Small frequent meals require you to schedule your day around your diet, which requires a lot of time and is often hard to incorporate into a busy schedule. Small frequent meals also tend to leave some people hungry, which can be a barrier to long-term adherence.


Leangains incorporates exercise into the fasting period. When you’re in a fasted state, since you consumed nothing in the previous hours, your body is already burning fat for energy. By exercising, you increase your body’s rate of fat burning, hence why the leangains methods advise that you workout in a fasted state prior to your first meal.

Focus your workouts on weight training. Weight training will help you build muscle mass and increase your metabolic rate. Utilize compound movements such as the deadlift, squat, bench press, pull up and overhead press, and focus on progressive overload (getting stronger on each exercise).

Large compound movements allow you to gain strength and muscle in the most time-efficient manner (3, 4 ).

The core of any decent weight training workout focuses on the deadlift, bench, and squat, also known as “the big three”.

The leangains guide recommends a 1-hour workout, at least 3-4 days per week - ideally 1 hour before your first meal.

Many people take around 20 g of BCAAs (branched-chain amino acids) prior to working out.

There are three branched-chain amino acids.

  • Leucine
  • Isoleucine
  • Valine

Leucine is responsible for protein synthesis, which drives muscle growth 5. By consuming leucine through a BCAA supplement prior to your workout, you prevent the breakdown of muscle tissue. At least, that’s what many people used to think.

Recent research is showing that taking BCAAs in a fasted state may be counterproductive for preventing muscle breakdown. The body sends a signal for protein synthesis when BCAAs are consumed, but because six of nine amino acids are missing with BCAAs alone, your body produces the remaining six from its own muscle tissue (6, 7, 8, 9).

Take 10 g of BCAAS 10 minutes before your workout, or preferably take 25 g (1 scoop) of whey protein about 30 minutes prior to your workout.

Both BCAAs and protein powder contains some calories and will spike insulin. But, don’t worry, this won’t “break your fast”.

Leangains Routine

  • A typical routine under the leangains protocol starts with a midday (12 pm) workout lasting one hour.
  • The workout is shortly followed by the beginning of the fed state at 1 pm (which should be your largest meal of the day).
  • Your second meal is at 4 pm.
  • Your final meal is at 9 pm.

This leangains routine tends to be popular as most people find it easy to fast directly after waking up. Being able to drink a cup of coffee in the morning makes fasting especially easy. A 1-9 pm leangains schedule feels like an early breakfast and late dinner. Although it is a matter of preference to chose which meals are bigger or if they are equal, it might be wiser to have two bigger meals (the first and the last one) and a smaller meal between them. Thus, you will get enough energy to recover from the fasting period at 1 pm and at 9 pm you will get enough energy to be able to complete all of your tasks during the fasting period.

It’s important to note that you don’t have to adhere to this specific routine. Everyone has different schedules and preferences. You can modify the hours to suit your schedule as long as you’re still fasting for 16 hours and eating for 8 hours.

Despite which time schedule you decide to go with, be sure to stay consistent with it. Maintaining a regular eating pattern will make the leangains diet easier to get used to.

Does Leangains Require Any Specific Dietary Requirements?

During your fasting period, black coffee, tea, diet soda, and sugar-free gum are fine as they contain zero calories. It’s perfectly fine to include a splash of milk in your coffee, and anything else which is under 10-20 calories.

The leangains protocol typically recommends a diet that cycles macros throughout the week. Your carbohydrate and calorie intake should be highest on the days that you train, with lower carbohydrate and higher fat intake during the rest of the days.

Your post-workout meal is recommended to be the largest meal of the day. During rest days, your first meal of the day should be your largest, accounting for around 40% of your daily calorie intake.

What Are The Benefits Of Leangains?


A large reason for many leangains success stories is because of the flexibility this protocol allows for. Some intermittent fasting schedules require you to eat only one or two large meals for the day. This has its benefits, but because leangains is closer to what you’re probably used to, it makes adhering to it easier.

It’s okay to be flexible. Whether or not your first meal accounts for 30% or 40% of your total daily calories is not what’s going to determine your success. Adherence is the most important metric for success 5. If you personally prefer to eat your largest meal at night, and that’s what helps you consistently get results, then, by all means, keep doing what works for you.

Increased Metabolism

Long periods of time can decrease your metabolism, due to adaptive thermogenesis 6. However, short term fasting may actually increase your metabolism (7, 8 ). One study on 11 healthy men found that a 3-day fast increased their metabolism by 14% 9. This could be due to increases in stress hormones such as norepinephrine.

Fasting may also improve your metabolic health by affecting signaling pathways which increase mitochondrial biogenesis, help with DNA repair and general metabolic health 10. There is also research that fasting at night could modify the gut microbiome, which may result in long term metabolic health improvements (11, 12).

Weight Loss

Leangains is incredibly effective for promoting weight loss. There are many claims out there that intermittent fasting is superior to other styles of eating for weight loss, but this isn’t completely true. You can lose weight eating two meals per day or eating eight meals per day. As long as the total amount of calories and protein you eat are matched, weight loss will not be different. Multiple meta-analyses have confirmed this (13).

However, it’s clear that for many people, intermittent fasting schedules such as leangains provide an advantage for weight loss (15). It’s harder to eat as much food when you’re restricting your feeding period. This causes an overall decrease in calorie intake, which over time, leads to a more consistent caloric deficit, driving greater weight loss.

May Improve Certain Health Conditions

By activating adaptive cellular stress response signaling pathways, intermittent fasting may be able to counteract disease processes (16, 17). It’s important to note that many studies exploring diseases such as Alzheimer’s, cancer and intermittent fasting are still in preliminary stages.

However, it’s clear that intermittent fasting is a viable health intervention for people who have high blood sugar levels and insulin resistance, namely type 2 diabetics. Research has shown that intermittent fasting reduces insulin by up to 31% and decreases blood sugar by 3-6% 18.

According to a 2016 published study, the leangains protocol can result in improved health-related biomarkers like reduced triglycerides, Insulin and blood glucose levels, reduced fat mass, and increased hormone adiponectine levels, which is related to increased energy expenditure.

What Are The Drawbacks Of Leangains?

As with all eating programs, there are some drawbacks and side effects to leangains. There are people with certain health conditions who should avoid time-restricted eating.

  • Eating disorders: Anyone who has an eating disorder should avoid any type of intermittent fasting routine. Intermittent fasting is healthy, but intermittent fasting can potentially turn into a form of abuse for someone with an eating disorder.
  • Pregnant and breastfeeding mothers: Pregnant and breastfeeding mothers or people with high caloric needs would also do well to avoid the restricted calorie plan of intermittent fasting.
  • Stress sensitivity: People who have a high sensitivity to stress should also take care when beginning an intermittent fasting protocol.
  • Counting macros is tedious: Most people simply don’t want to spend time counting and weighing every meal.

Are There Any Side Effects Of Leangains?

You may potentially experience:

  • Hunger
  • Headaches
  • Heartburn
  • Tiredness
  • Dizziness
  • Irritability
  • Cold fingers and toes

You may not experience any side effects, or you may experience several. Everyone’s different. Your body will adapt over the first few weeks, and symptoms should subside. If they don’t, then consider stopping intermittent fasting, or at the very least, eat more food.

How To Calculate Leangains Macros

Step 1: Calculate Your BMR

The first step in calculating your required macros is to calculate your BMR or basal metabolic rate. Your BMR is the amount of energy you require to maintain your body weight in a non-active state.

To calculate your BMR, you can use this online calculator.

Step 2: Calculate Your TDEE

The second step in calculating your leangains macros is to adjust your BMR to your activity level and calculate your total daily energy expenditure (TDEE) with the method below.

  • Sedentary (little to no exercise): TDEE = BMR x 1.2
  • Lightly active (exercises 2-3 days a week): TDEE = BMR x 1.375
  • Moderately active (exercises 4-5 days a week): TDEE = BMR x 1.55
  • Very active (exercises 6-7 days a week): TDEE = BMR x 1.725
  • Extremely active (exercises twice per day, high intensity): TDEE = BMR x 1.9

To calculate your TDEE, you can use this online calculator.

Step 3: Adjust Your TDEE

The third step in calculating leangains macros is to adjust your TDEE based on a goal to figure out your average daily calorie intake target.

A calorie deficit is required for weight loss, and as TDEE is your daily expended energy, you simply need to have an energy (or calorie) intake lower than your TDEE.

Because the speed of weight loss depends on body fat percentage, it is best to make changes to TDEE based on your matching body fat percentage, as demonstrated by the calculations below.

For body fat percentage of:

  • 30%+ reduce calorie intake (TDEE) by 30%
  • 20-30% reduce calorie intake (TDEE) by 25%
  • 10-20% reduce calorie intake (TDEE) by 20%
  • 10% reduce calorie intake (TDEE) by 15%

Note: If you’re using leangains for muscle growth, then simply increase your TDEE/calorie intake by 20%.

Step 4: Adjust Your Daily Calorie Intake

Adjust your caloric intake for active and rest days. There should be a 40% difference between training and rest day calorie intake.

For those training for 3 or 4 days a week, a simple calculation is:

  • Active day calorie intake = average daily calorie intake x 1.2
  • Rest day calorie intake = average daily calorie intake x 0.8

Step 5: Calculate Your Leangains Macros

The final step of the process is to calculate your leangains macros. This involves dividing your active and rest day calorie intakes between three macronutrients (protein, carbs and fat).

Protein levels will be high with carbohydrate and fat intake levels cycling between active and rest days.


  • 2.5g of protein per kilogram (1.2 g/lb) of lean body mass (rest and active days)


  • Average daily intake = 0.9-1.3g per kilogram (0.43-0.62 g/lb) of lean body mass
  • Rest day intake = increase daily intake by 30%
  • Active day intake = decrease daily intake by 30%


To calculate your carbohydrate intake you simply balance out what is left in your daily calorie targets, with carbohydrates having 4 calories per gram. Use the rest and active daily calorie intakes from step 4.

  • Rest day carb intake = Rest day calorie intake - Rest day fat intake - Rest day protein intake
  • Active day carb intake = Active day calorie intake - Active day fat intake - Active day protein intake

Divide the daily carb intake by 4 to then calculate your average daily grams of carbohydrates.

While the math might seem overwhelming, it is relatively simple once you start and there are online calculators available for all of the equations. For an easier way to visualize these calculations, then refer to the simplification below.

BMR → TDEE → Average Daily Calorie Intake → Active/Rest Adjustment → Macros

Does all of this seem overcomplicated? Here are your options:

Don’t count macros: You can also decide not to count your calories and macros. Plenty of people lose weight doing this, and intermittent fasting is exactly what helps them do so. Consuming enough protein and exercising can be more than enough to keep you in a calorie deficit and induce weight loss.

Count macros without being too accurate: To make your life easier, use this leangains macro calculator which will help you figure out your leangains macros in under five minutes.

Then simply take one of two paths:

  • To build muscle: + 500 calories to your TDEE
  • To lose fat: - 500 calories from your TDEE (and up to -1000 if you weigh more)

Bottom Line

Leangains is a simple and easy form of intermittent fasting to follow. Simply eat for 8 hours, fast for 16 hours and get stronger in the gym. Leangains can help you lose weight, stay healthy and retain your hard earned muscle. While setting up the leangains routine into your life can be a bit tedious at first, once you’re used to the lifestyle change, you’ll find that it’s simple and easy to adhere to.

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