What Is The Energy In And Out Balance?

Energy balance refers to the relationship between “energy in” and “energy out” in the human body. Energy balance is achieved when the amount of energy consumed in food (energy in) equals the amount of energy expended through basal metabolism, physical activity, and other functions (energy out). Maintaining energy balance is important for maintaining a healthy body weight and preventing unhealthy weight gain or loss.

Energy balance impacts overall health and wellbeing. An imbalance between energy in and energy out over time can lead to weight gain or weight loss. Gaining too much weight or becoming overweight/obese increases risk for chronic diseases like heart disease, diabetes, cancer and more. Losing too much weight or becoming underweight can negatively impact immunity, bone health, menstruation and fertility in women, and other aspects of health.

Understanding energy balance allows individuals to make informed choices about diet and exercise to achieve and maintain a healthy body weight. Small consistent changes to energy in and/or energy out can make a big difference over time. Strategies for improving energy balance include decreasing calorie intake from foods and beverages, increasing levels of physical activity, and making healthier overall lifestyle choices.

Energy In – Food Intake

The energy we get from food is measured in calories. Calories are a measure of how much energy a food provides. The number of calories you need each day depends on your age, sex, height, weight, and activity level.

There are three main types of calories that provide energy:

  • Carbohydrates – 4 calories per gram
  • Protein – 4 calories per gram
  • Fat – 9 calories per gram

Calorie density refers to the number of calories in a given weight of food. Foods like fats, oils, nuts, seeds, and sweets are considered high-calorie dense. They provide a lot of calories in a small portion. Foods like fruits, vegetables, and lean proteins are low in calorie density.

Factors that can affect food intake and total caloric consumption include appetite, food preferences, portion sizes, social settings, emotions, schedules, cost, access, culture, and habits. Being aware of these factors can help with making better food choices.

Energy Out – Basal Metabolism

Basal metabolism refers to the amount of energy your body uses at rest to maintain normal body functions like breathing, blood circulation, cell and organ function. It makes up the largest portion of your total daily energy expenditure. Basal metabolic rate (BMR) is the number of calories your organs need to function if you stayed in bed all day.

Some key factors that affect BMR include:

  • Body size and composition – People with more muscle mass tend to have a higher BMR.
  • Age and sex – Men usually have a higher BMR than women. BMR generally decreases as you age.
  • Genetics – Some people inherit a naturally faster or slower metabolism.

While you can’t change some factors like age and genetics, building muscle through exercise and strength training can help increase your BMR. Overall, basal metabolism accounts for 60-75% of total daily calorie needs for most people.

Energy Out – Physical Activity

Physical activity is any movement of the body that burns calories. The more intense the activity, the more calories burned. There are many different types of physical activity:

  • Aerobic exercise like walking, running, swimming, and dancing
  • Strength training with weights or resistance bands
  • Yoga and Pilates
  • Team sports like soccer, basketball, and volleyball
  • Household chores like vacuuming, gardening, and cleaning

The amount of calories burned depends on the duration and intensity of the activity. Higher intensity activities like running burn more calories per minute compared to lower intensity activities like walking. But all physical activity contributes to energy expenditure.

There are calculators and charts that provide estimates of calories burned for various activities. These can give you a rough idea, but the actual amount can vary substantially based on the individual, their fitness level, effort exerted, etc. The more lean muscle mass a person has, the more calories they will burn during exercise. Tracking calories burned by using an activity tracker or heart rate monitor can provide more personalized estimates.

Increasing physical activity is an important component of balancing energy in and out. Both cardio and strength training provide health benefits beyond just burning calories. Being active helps regulate appetite hormones, reduces stress, builds muscle mass, and lowers the risk of many chronic diseases.

Energy Imbalance and Weight

When you consume more energy than you burn, this results in a calorie surplus and energy imbalance. Any excess energy that is not used will be stored on your body as fat for later use. Over time, this can lead to weight gain. Conversely, when you burn more energy than you take in, this creates a calorie deficit and energy imbalance. Your body will need to use stored body fat to make up this energy deficit, resulting in weight loss over time.

To gain weight, you need to be in a calorie surplus, consuming more calories than you burn on a regular basis. For weight loss, you need to be in a calorie deficit, burning more calories than you consume. Even a small energy imbalance over the long-term can lead to gradual weight change. A deficit or surplus of just 500 calories per day could result in 1 pound gained or lost per week.

That’s why balancing your energy in and out is crucial for maintaining a stable weight long-term. When your energy intake matches your output, you are in energy balance. Tracking calories, being mindful of portions, and staying active can help you achieve balance and maintain a healthy weight.

Tips for Achieving Energy Balance

To achieve energy balance, the key is to balance the calories you take in from food and drink with the calories you burn through physical activity. Here are some tips to help you reach energy balance:

Reduce Calorie Intake

Pay attention to portion sizes and limit intake of high calorie foods and beverages. Fill up on non-starchy vegetables and fruits which provide nutrients with fewer calories. Avoid oversized portions and second helpings. Drink water instead of sugary drinks.

Increase Activity Level

Aim for 150 minutes per week of moderate intensity activity like brisk walking. Also incorporate muscle-strengthening exercises 2 times per week. Take the stairs, park farther away, walk during lunch, and find other ways to move more throughout your regular day.

Track Intake vs. Output

Use an app to track your food and beverage intake along with your physical activity. This can help you understand your personal energy balance. Adjust your habits over time to reach your calorie goals and achieve energy balance for weight management.

Common Misconceptions

There are some common myths and misconceptions when it comes to energy balance and weight loss. Two of the biggest ones are related to metabolism and starvation mode.

Many people believe that being overweight is caused by having a “slow metabolism.” While metabolic rates do vary from person to person, this variation is much smaller than most people think. Studies show that the difference in resting metabolic rate between those with “fast” and “slow” metabolisms is only about 200-300 calories per day. Things like age, genetics, and body composition play a role in metabolic rate, but in general, metabolism is not a major factor in weight gain/loss.

Another myth is that severely restricting calories will cause the body to go into “starvation mode” and hold onto fat. In reality, moderate calorie deficits of 20-25% are safe and do not cause metabolic slowdown or starvation mode. Very low calorie diets can sometimes temporarily reduce metabolism by a small amount, but not to a degree that prevents weight loss. As long as the deficit is reasonable for one’s body weight and activity level, starvation mode is generally not a concern.

Special Considerations

Achieving energy balance can become more complicated based on factors like age, gender, health conditions, and life stages like pregnancy and lactation. Here are some key points on special considerations for energy balance:

– Age affects energy needs. Children and adolescents require more calories per pound than adults to support growth and development. As we age, our metabolism slows down and energy needs decrease.

– Men generally have higher energy needs than women due to greater muscle mass and higher metabolic rates.

– Certain health conditions like diabetes, thyroid disorders, and injuries can impact energy needs and make balancing intake and expenditure more difficult.

– Pregnant and breastfeeding women require additional calories to support a growing baby. However, needs vary based on the trimester for pregnancy and age of infant for lactation.

Consulting with a healthcare provider or dietitian can help determine appropriate energy needs based on individual factors like age, gender, health status, and life stage. Tracking intake and weight over time can also help determine energy balance.

Importance of Nutrient Quality

While total calories are an important part of energy balance, it’s also critical to consider nutrient quality. The foods and beverages we consume provide energy in the form of macros – protein, fat and carbohydrates. But they also supply essential vitamins, minerals, phytochemicals and fiber that support optimal health.

When focusing solely on calories, it’s easy to fill our plates with processed choices or empty carbs that lack nutrients. However, the most nutritious options like fruits, vegetables, whole grains, lean proteins, healthy fats and low-fat dairy pack the most nutritional punch per calorie. Choosing more nutrient-dense foods as part of a balanced diet provides vital micronutrients, antioxidants, and compounds that may help reduce disease risk.

So when aiming for energy balance, be sure to emphasize nutrients in addition to calories. Fill half your plate with fruits and veggies, include fiber-rich whole grains, choose lean and plant-based proteins, and avoid empty calorie choices. Proper nutrition combined with managing calories in versus calories out is the recipe for optimal health.


In conclusion, energy balance refers to the balance between the number of calories you consume (energy in) and the number of calories you burn (energy out). To maintain a healthy weight and optimal health, it is important to achieve energy balance where energy in equals energy out. This requires paying attention to your dietary intake, physical activity levels, and making adjustments when necessary to avoid prolonged periods of calorie excess or deficit. Focus on eating a nutritious diet full of whole foods and getting regular exercise. With some mindful awareness of your energy balance, you can maintain a healthy lifestyle.

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