Leangains: A Guide To Intermittent Fasting

One diet strategy that’s taken the fitness world by storm is intermittent fasting. Intermittent fasting (IF) is simply a defined period of time where you eat and don’t eat. Most see it as a less restrictive way for people to lose weight. The Leangains diet has taken the IF concept and added a strength-building twist to it. Let’s discuss how it works.

Understanding Intermittent Fasting Leangains Style

Leangains is a diet popularized by a Swedish nutritionist, Martin Berkhan. He emphasizes intermittent fasting and lifting heavy weights to help people lose weight while maintaining muscle mass.

The main approach to Leangains is this:

Eat all of your daily calories in an 8-hour window and fast the other 16 hours of the day. During the fasting portion, you can drink zero-calorie beverages but is prohibited from consuming any calories. This can easily be accomplished by not eating several hours before bed and skipping breakfast in the morning.

For example, you can start fasting at 7 pm, going to sleep at 10 pm, waking up at 7 am, and not eating until 11 am the next day. Within the 8-hour eating window, you can eat foods that are high in calories. The emphasis is more calories on workout days and fewer calories on non-workout days. It may take your body about a week to adjust to the Leangains style of eating.

How to Create a Leangains Diet

Like other intermittent fasting style diets, Leangains places emphasis on eating/non-eating time intervals.
What separates Leangains from the other if protocols are the emphasis on maintaining muscle mass and building strength. This helps your muscles be more defined when losing weight and lowering your body fat percentage.

Creating a Leangains diet is fairly simple. There are 12 rules that you need to abide by:

  1. Choose an 8-hour eating window that’s convenient for you. Fast for the remaining 16 hours
  2. Skip breakfast (i.e., don’t eat for a few hours after waking up) since it’s easier to stay fasting after sleeping for 7-8 hours.
  3. Don’t eat any calories during your fasting period. It’s okay to drink zero-calorie beverages or chew sugar-free gum though.
  4. Be prepared to handle hunger pain for the first 3-7 days of the diet, especially you’re an avid breakfast eater. After that, you should be fine.
  5. Try to keep meal intake between 2-3 meals per day
  6. Be sure to consume at a meal within 2 hours after working out
  7. Try to train while in a fasted state to increase the fat burning effect
  8. When training fasted, take 10 grams of a BCAA pre-workout shake to get an energy boost
  9. On training days, consume most of your calories post-workout
  10. On training days, most of your calories will be high carb/low fat intake
  11. On non-training days, your caloric intake will be decreased
  12. On non-training days, your caloric intake we are high fat/low carb

Now, don’t let all the rules overwhelm you. The Leangains diet is actually quite simple to implement and is applicable to most schedules. Here is an example of an average-sized man who works out in the morning can implement Leangains:


Leangains Calculators: How To Determine Calories & Macros

The following is the complete guide on how to calculate your calories and macros.

Calculating Calories

Step 1: Calculate Your BMR

Whether losing weight or building muscle, knowing your basal metabolism rate (BMR) is very important. Your BMR is the calories your body requires to maintain functionality while at rest. In other words, if you were in a coma, this would be all the calories you would need to survive.

The Harris-Benedict formula is commonly used to calculate BMR but isn’t very effective because it doesn’t take body fat percentage or muscle mass into account. Instead, use the Katch-McArdle formula to calculate formula:

BMR = 370 + 21.6 * Lean Body Mass

Note: Lean Body Mass is in kg. To convert pounds to kg, just divide your weight by 2.2.

Here is how to find your Lean Body Mass (LBM):

LBM = weight – (weight * (body fat percentage/100))

To get an accurate reading of your body fat percentage and LBM, I recommend getting a DEXA scan.

Step 2: Determine Your Physical Activity Level

Assuming you’re not in a coma, you perform some sort of physical activity every day. The question is what level you fall under. To determine this, you must add an ‘activity multiplier’ (x1.2 – x1.9) to your BMR:

  • Sedentary (little or no exercise): BMR x 1.2
  • Lightly active (training/sports 2-3 days/week): BMR x 1.375
  • Moderately active (training/sports 4-5 days/week): BMR x 1.55
  • Very active (training/sports 6-7 days a week): BMR x 1.725
  • Extremely active (twice per day, extra heavy workouts): BMR x 1.9

Once you have this number, you now know your total daily energy expenditure (TDEE) number.

Step 3: Determine Caloric Intake Based On Your Fitness Goal

Now that you have your TDEE, it’s time to determine what your fitness goal. For most people, they either want to burn fat or build muscle. It is very important that you know which one you want to achieve so you can properly calculate your caloric intake.

Goal: Fat Loss

To lose body fat, the main focus should be to reduce caloric intake. The more body fat you have, the more calories you need to shave off your TDEE. Check out this table:


Again, I recommend getting a DEXA scan to determine your body fat percentage.

Goal: Build Muscle

To build muscle, simply increase TDEE by 20 percent.

Step 4: Calculate Caloric Intake For Training & Non-Training Day

The last step for calculating calories is determining caloric intake for training and non-training days. When following Leangains, you will eat more calories on workout days vs. rest days. This was purposely designed to optimize recovery.

Here are the equations for both days:

TDEE * 1.2 = Training Day Caloric Intake

TDEE * 0.8 = Rest Day Caloric Intake

Calculating Macros

Now that you have a defined caloric intake, it is time to calculate your macros. Strategically consuming your macronutrients (protein, fat, & carbs) is an integral part of the Leangains diet.

Step 5: Determine Your Protein Intake

Of the three macronutrients, protein will usually be the highest ratio. Protein is the building blocks of muscles, so its importance is without question, especially after a strenuous workout. In addition, it helps protect muscle mass while dieting down and losing weight. Your fitness goal will determine how much protein you should intake on a daily basis.

Goal: Fat Loss

When trying to shed body fat, research suggests that your protein intake should be about 2.3-3.1 g/kg (~1.1-1.4 g/lb) per lean body mass. For example, if your LBM is 140lb (63.5 kg), then you should aim for 154-196 grams of protein per day. Any lower than that number and you risk losing muscle mass.

Goal: Building Muscle

When trying to bulk up and build muscle, you should aim to get slightly less protein per LBM than fat loss: 1.6-2.2 g/kg (~0.8-1.0 g/lb). So the same guy who has 140lb of LBM would be consuming 112-140 grams of protein per day.

While some think you need to actually consume more protein than this, that’s really not going to help you unless you’re on steroids or other muscle-building drugs. However, to maximize your bulking efforts, I suggest consuming as much protein as you weigh in LBM every day.

Step 6: Determine Your Fat Intake

Don’t let these fad diets fool you. Fat intake helps regulate your hormones, so it essential that you get enough per day. For daily fat intake, aim to get 0.9 g/kg (~0.4 g/lb) of LBM regardless of your fitness goal.

For Leangains, remember that fat intake will be higher on rest days than training days. The reason for this is to maximize calorie partition. (e.g., improved workout recovery, better fat loss)

Goal: Fat Loss

To burn body fat, aim for the following fat intake per day: 0.9-1.3 g/kg (~0.4-0.6 g/lb) of LBM. On rest days, increase that number by 30 percent. On training days, decrease that number by 30 percent.

Goal: Building Muscle

To build muscle, your daily fat intake should be around 20-30 percent of total calorie intake. (Keep in mind that there are 9 calories for each gram of fat) On rest days, multiply that number by 1.3 to get fat intake. On training days, multiply that number by 0.7 to get fat intake.

Step 7: Determine Your Carb Intake

Carbs finish the macro equation. Carbs are essential because it provides energy and helps with muscle building, restoration, and recovery. Regardless of your fitness goal, here is how to calculate carbs for your rest and training days.

  • Rest day carb intake = Rest day calorie intake – Rest day fat intake – Rest day protein intake
  • Training day carb intake = Training day calorie intake – training day fat intake – training day protein intake

To make it easier to get your caloric and macro intake, go here to use the Leangains calculators.

Leangains guides

While there are many ways to implement Leangains. The creator of the diet, Martin Berkhan, suggest fasting through the night and morning time. This will be the easiest way for most people to since you’re automatically fasting while asleep.

Here is a quick example of someone who works out in the early morning:

  • 6 AM: 5-15 minutes pre-workout: 10 g BCAA.
  • 6-7 AM: Training.
  • 8 AM: 10 g BCAA.
  • 10 AM: 10 g BCAA
  • 12-1 PM: The “real” post-workout meal (largest meal of the day). Start of the 8-hour eating-window.
  • 8-9 PM: Last meal before you restart your 16-hour fast

On non-training days, you won’t need any BCAA supplementation. Just don’t eat anything until noon.

Leangains Reddit

The Leangains section has over 90,000 subscribers on Reddit. So this is an ideal forum to join, especially for those who are starting the diet and needs guidance.

Are Leangains Diets Safe?

From most users’ experience, Leangains is considered a safe diet. There haven’t been any reports of bad side effects as of now. The only thing is some people will have to overcome hunger pains and/or light headaches during the first week. This is merely the body adjusting to the new eating style.

Leangains Workouts for Best Results

Unlike other intermittent fasting diets, Leangains require you to workout.

Martin Berkhan’s workout philosophy


Martin’s workout emphasis is this: Train hard and heavy. He prefers to focus on strength, regardless of the focus is fat loss or building muscle. He places emphasis on using big compound movements (bench press, squats, deadlifts, chin-ups) and training 3 days per week. Workouts should take no longer than an hour.

Reverse Pyramid Style

Reverse Pyramid Training (RPT) is a style of training where you perform your heaviest set first, and then decrease the weight for the next set. For example, you start at 205lb for 5 reps for the 1st set, 195lb for 6 reps for the 2nd set, and 185lb for 8 reps for the 3rd set.

RPT is what Martin and most other Leangain users do.

Warming up

To warm up for RPT training, determine the heaviest weight you going to use for the 1st set of the first exercise. Then, you perform 3 sets for your warm-up in the following fashion:

  • 5 reps with 60 percent of the weight you’re going to use in your first set
  • 3 reps with 75 percent
  • 1 rep with 90 percent

How Long Should You Rest?

Rest periods should be between 2-3 minutes per set. This should give you enough time to recuperate while keeping training level high.

What Exercises To Do

Focus on compound movements or exercises that target multiple muscle groups:

  • Bench press
  • Overhead press
  • Deadlifts
  • Chin-ups/Pull-ups
  • Barbell row
  • Lunges
  • Most dumbbell exercises (rows, chest press, shoulder press, etc.)

Final Word on Leangains

Whether your goal is to burn fat or build muscle, Leangains is a good diet to try out. It can help people improve their caloric intake and eating habits. It also does a good job of advocating about the importance of lifting heavy as this will help people build a strong, dense physique.

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