A calorie is a unit of energy that measures the energy content in food and drinks, which your body uses to power all metabolic processes, including basic functions like breathing, circulation, and digestion. The minimum energy required to keep your body functioning at complete rest is the Basal Metabolic Rate (BMR). The total number of calories you need to consume is the Total Daily Energy Expenditure (TDEE), which includes your BMR plus the energy used for daily movement. The specific TDEE for any 135-pound woman is highly unique, as weight is only one variable in a complex calculation.
Determining Maintenance Calorie Needs
Calculating the calories needed to maintain 135 pounds requires accounting for several individual factors. Age, height, and daily activity level are significant determinants of the final TDEE number. The Mifflin-St Jeor equation is widely considered a reliable formula for estimating BMR, which establishes your baseline energy requirement before any movement is factored in.
Once BMR is established, it is multiplied by an activity factor to determine TDEE, which represents maintenance calories. For example, a 135-pound woman who is 5’5″ and 30 years old would have a BMR of approximately 1,333 calories. This baseline is then adjusted based on her lifestyle, resulting in a broad range of potential maintenance needs.
A woman with this profile who is largely sedentary, meaning she has a desk job and performs little to no exercise, would have a TDEE around 1,600 calories per day. Conversely, a woman who is moderately active, engaging in three to five days of structured exercise per week, would see her TDEE increase to approximately 2,066 calories. This difference highlights the impact of activity level.
For a highly active woman who trains intensely six or seven days a week, the maintenance calorie need could rise to around 2,300 calories or more. This difference demonstrates why relying on a single number for a 135-pound woman is inaccurate. Actual movement throughout the day, including non-exercise activities like walking and fidgeting, is a major component. Accurately assessing your true activity level is the most important step in finding your maintenance calorie target.
Adjusting Intake for Weight Goals
The TDEE represents the intake required to keep your weight stable. To achieve any weight goal, you must strategically create a controlled imbalance by consuming fewer or more calories than this maintenance figure. For weight loss, the most sustainable approach is establishing a daily calorie deficit of about 500 calories. Reducing intake by this amount below your TDEE is commonly associated with losing about one pound per week.
This 500-calorie daily adjustment is a practical starting point, though the traditional 3,500-calorie rule for a pound of fat is an oversimplification of metabolism. As the body loses weight, its energy needs naturally decrease, meaning the rate of weight loss will slow over time even with a constant deficit. Consulting a professional, such as a registered dietitian, is advisable before making extreme calorie reductions to ensure nutritional requirements are met.
If your goal is to gain muscle mass, a slight calorie surplus is necessary to fuel tissue growth. An increase of 100 to 300 calories above your maintenance TDEE is typically sufficient. This surplus must be coupled with an increased emphasis on protein intake. Protein provides the amino acids that serve as the building blocks for new muscle tissue during a muscle-building phase.
Prioritizing Nutrient Quality Over Quantity
Focusing solely on the calorie number without regard for the source can undermine health and weight management efforts. The TDEE is merely a mathematical estimate of energy needs; the quality of the food consumed determines metabolic function and satiety. A diet rich in nutrient-dense foods provides better fuel and supports bodily processes more effectively than one composed of empty calories.
Protein intake is important because it has a higher thermic effect than fats or carbohydrates, meaning the body expends more energy to digest it. Adequate protein also promotes satiety, helping to manage hunger and control overall calorie intake. Complex carbohydrates, found in whole grains and vegetables, offer a steady supply of energy, unlike simple sugars that can lead to rapid spikes and crashes in blood sugar.
Dietary fats are necessary, as they play a direct role in hormone production and the absorption of fat-soluble vitamins. Beyond the three macronutrients, micronutrients like vitamins and minerals function as cofactors necessary for countless metabolic reactions. Even if a person hits their TDEE goal, a deficiency in a single micronutrient can impair the efficiency of energy conversion and other fundamental biological processes.