Bulk Up or Lean Out? Tailoring Your Diet to Your Goals


When it comes to fitness and bodybuilding, one of the most common dilemmas individuals face is whether to bulk up or lean out. Both approaches have their merits and are driven by distinct goals. However, for those seeking a more sustainable and long-term approach, the concept of main-gaining offers a versatile strategy. In this article, we’ll delve into the science behind bulking, leaning out, and main-gaining, and discuss how to tailor your training regimen to align with your goals while prioritising sustainability and effectiveness. 

Bulking Up:

Bulking up typically involves consuming a caloric surplus combined with resistance training to stimulate muscle growth. The premise behind bulking is to provide the body with excess energy to support muscle hypertrophy while engaging in progressive overload through resistance exercises. This surplus of calories is essential for providing the necessary building blocks for muscle repair and growth.

Research has consistently shown that consuming a caloric surplus is conducive to muscle gain. A study published in the Journal of the International Society of Sports Nutrition found that participants who consumed a high-calorie diet alongside resistance training experienced significant increases in muscle mass compared to those on a maintenance diet. This underscores the importance of energy surplus in facilitating muscle growth.

Furthermore, resistance training plays a pivotal role in stimulating muscle protein synthesis, a key process in muscle hypertrophy. Studies have demonstrated that resistance exercises induce anabolic signalling pathways, promoting muscle protein synthesis and ultimately leading to muscle growth. A review published in Sports Medicine highlighted the effectiveness of resistance training in enhancing muscle hypertrophy across various populations.

However, it’s essential to note that bulking up may also lead to increases in body fat due to the surplus of calories. While some degree of fat gain is inevitable during a bulk, excessive fat accumulation can be detrimental to overall health. Therefore, it’s crucial to monitor calorie intake and prioritise nutrient-dense foods to minimise fat gain while maximising muscle growth.

Leaning Out (Shredding):

On the other hand, leaning out involves reducing body fat while preserving lean muscle mass. This typically entails consuming a caloric deficit combined with cardiovascular exercise and resistance training. The goal of leaning out is to reveal muscle definition by shedding excess body fat, resulting in a more aesthetic and defined physique.

Numerous studies have demonstrated the efficacy of a caloric deficit in promoting fat loss. A meta-analysis published in Obesity Reviews concluded that energy restriction is the primary determinant of weight loss, highlighting the importance of calorie control in achieving a lean physique. By consuming fewer calories than the body expends, individuals create an energy deficit, prompting the utilisation of stored fat for fuel.

In addition to calorie restriction, incorporating both cardiovascular exercise and resistance training is essential for optimising fat loss while preserving muscle mass. Cardiovascular exercise, such as running or cycling, increases energy expenditure and enhances fat oxidation, contributing to overall calorie deficit. Meanwhile, resistance training helps maintain muscle mass during periods of calorie restriction by preserving muscle protein synthesis and preventing muscle breakdown.


Contrary to the bulking and cutting approach, maingaining offers a different perspective on achieving body recomposition. Rather than cycling through periods of calorie surplus and deficit, maingaining emphasises the importance of adhering to maintenance calories. This entails ensuring that energy intake matches energy expenditure to maintain a stable body weight and composition. While adjustments to calorie intake may be necessary based on lifestyle changes or activity levels, the primary goal remains to sustain a balanced energy equation without resorting to periods of calorie surplus or deficit. In essence, maingaining promotes a gradual body recomposition process where individuals strive to build muscle and lose fat simultaneously through consistent training with progressive overload, albeit at a slower pace compared to traditional bulking and cutting cycles. This sustained effort allows for steady progress in both strength and physique development, fostering long-term results.

Who should opt for Main-Gaining? It’s not for those seeking rapid muscle gains or significant body transformations in a short period. If you’re still in the early stages of your fitness journey and aiming for drastic changes in body composition, traditional bulking, cutting, or recomposition methods might be more suitable. However, Main-Gaining is ideal for individuals who prioritise sustainability and balanced progress over quick fixes. It’s particularly beneficial for those who struggle with extreme dieting or have difficulty controlling bulking phases. If you’re looking to maintain your current physique while gradually improving muscle tone and definition, Main-Gaining offers a practical and effective approach, especially for seasoned lifters seeking long-term progress without the pitfalls of extreme calorie cycling.

Bulking, Shredding or Maingaining?

Now, whether your goal is to bulk up, lean out, or main-gain, understanding the underlying principles behind each approach is essential for designing an effective training regimen. By incorporating scientific and academic research into your training approach, you can tailor your workouts to align with your specific goals and maximise your results in the gym. Whether you choose to focus on building muscle, shedding body fat, or pursuing a balanced approach, consistency, patience, and adherence to sound principles will ultimately determine your success in achieving your fitness objectives.