Nutrition for bulking and cutting explained

Amy Brownstein, MS, RDN - Registered Dietitian Nutritionist

Popular diet cycles among bodybuilders and gym-goers, bulking and cutting are explained as methods to build muscle and reduce body fat. Read on to learn the concepts of bulking and cutting, as well as the different nutrition recommendations for each phase.

Bulking and cutting explained

Cycling between bulking and cutting is a popular diet cycle used by physique athletes or bodybuilders. It has recently become more mainstream, frequently incorporated into gym culture.

The goal of bulking is to gain muscle mass. It requires consuming a calorie surplus and engaging in strength training to support muscle growth and strength gains. However, not all weight gain during bulking is due to increases in muscle mass. Some fat gain accompanies muscle growth during bulking.

Conversely, cutting refers to the process of reducing body fat while maintaining muscle. Cutting requires eating in a calorie deficit while continuing to strength train to maintain muscle mass. The goal of cutting is to reveal muscle definition.

People cycle between bulking and cutting to efficiently build muscle (bulking) and then reveal that muscle definition (cutting). Bulking and cutting reshape body composition over time. It is a common practice among bodybuilders.

However, bulking and cutting are not without some potential issues. Strict eating habits during periods of bulking and cutting can lead to disordered eating. Yo-yo dieting and significant weight fluctuations, often associated with bulking and cutting, can negatively affect health, including increasing the risk of developing type 2 diabetes later in life.

Nutrition tips for how to bulk and cut

Limited research exists on nutritional guidelines for bulking and cutting. The methods originated with physique or bodybuilding competitions, with these dietary phases correlating with training cycles. Additionally, recommendations are highly specific, depending on the motivation and cycle length.

Nutrition recommendations for bulking

Calories: Recommendations for caloric intake to gain bulk vary depending on the individual's specific needs. However, the bulking phase generally requires a 10 to 20% increase in caloric intake.
Protein: Recommendations for protein range from 1.6 to 2.7 grams per kilogram of body weight per day.
Carbohydrates: Even during the bulking period, many physique athletes have a low carbohydrate intake. Although recommendations suggest consuming anywhere from 4 to 7 grams of carbs per kilogram of body weight, many athletes actually consume only 3 to 5 grams per kilogram of body weight.
Fat: Fat intake is moderate during the bulking period, accounting for 15 to 25% of total caloric intake.

Nutrition recommendations for cutting

Calories: Recommendations for caloric intake for cutting vary depending on the individual, goals, and the projected timeline for meeting these goals
Protein: Some recommendations suggest 2.3 to 3.1 grams of protein per kilogram of lean body mass. Determine lean body mass using DEXA scans or specific calculations. Lean body mass provides a more accurate estimate of protein needs. Higher protein needs are required to preserve lean muscle mass with the intense calorie deficit often associated with the cutting phase. When such a large percentage of overall caloric intake comes from protein, you miss out on other essential nutrients. Therefore, the cutting phase should be temporary.
Carbohydrates: Depending on your goals, carbohydrate intake may be as low as 2 to 5 grams per kilogram of body weight. This translates to roughly 136 to 340 grams of carbohydrates per day for someone who weighs 150 pounds. However, other research suggests that carbohydrate intake should remain between 4 and 7 grams per kilogram of body weight. Carbohydrates are essential for maintaining optimal training performance and facilitating post-training recovery. Bodybuilders who consume more carbohydrates appear to place higher in competitions than those who more intensely restrict carbohydrates.
Fat: Aim for 10 to 25% of calories from fat, prioritizing healthy unsaturated fats. Recent research suggests that a low-calorie diet during the cutting phase may be a greater contributor to negative changes in testosterone levels compared to reduced fat intake. Still, prolonged periods of a very low-fat intake are discouraged due to the potential to disrupt hormone levels.

Bulking and cutting tips

Space protein intake evenly throughout the day.
Eat a meal containing a mix of protein, carbohydrates, and fat within two hours after training to help prevent potential performance decreases.
You may need to eat more meals more frequently during the bulking phase to account for the necessary increase in caloric intake.
Prepare food ahead of time to ensure balanced meals.
Utilize spices, herbs, lemon juice, and vinegars to add variety and prevent flavor fatigue.
Consider taking a multivitamin during the cutting period to help combat any nutrient deficiencies that may occur with a low-calorie, protein-rich diet.
Slower weight loss is more favorable for health. Allow yourself plenty of time for weight loss and adjust your calorie deficit to achieve gradual weight loss.

Tracking your bulking and cutting progress with MyNetDiary explained

Use the MyNetDiary app to track food, exercise, and progress.

The MyHealth feature provides a space to enter body measurements, including waist and hip size, as well as body fat percentage.
Under the “Me” tab, utilize “Progress Photos” to visually track changes to your body composition and appearance. If you're training for a bodybuilding competition, Progress Photos may be a good place to see changes in your competition poses.
Log your meals on MyNetDiary to track overall calorie intake and ensure you meet your protein, carbohydrate, and fat targets.

With the benefits and concerns of bulking and cutting explained, you can make an informed decision as to whether incorporating cycling of these weight-loss methods is best for you and your healthier lifestyle.