If you’ve ever tried to shed weight, you’ve likely heard that a calorie deficit is needed. Yet, you may wonder why it’s necessary for weight loss or what exactly it involves.
This write-up discusses everything you need to understand about a calorie deficit, including how it affects weight loss, what it is, and how to achieve it in a sustainable, healthy way.
A calorie is a unit of energy. It is the amount of heat required to raise the temperature of 1 gm (gram) of water by 1 degree Celsius. Calories in food offer energy in the form of heat so that your bodies may function even when they are at rest [1].
The total number of calories we burn on a daily basis is called our TDEE or total daily energy expenditure. When TDEE is calculated, it includes:
To figure out how many calories our body requires to perform basic functions, we can estimate our RMR or (resting metabolic rate ). Once we know our RMR, we can use a calculator to estimate our total daily energy expenditure. We can also get it tested in a health club or lab setting [2].
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Most people take more calories than they require to maintain their weight every day. When we consistently eat more calories than our body requirements, the additional calories are stored as fat.
So how do we get rid of extra fat and lose weight? We create a calorie deficit. This energy deficit happens when we eat less during the day. If our body doesn’t get the calories it requires to perform all of its necessary functions, we create a calorie deficit. Stored fat is stored energy.
Our body can use it to keep moving rather than using energy from food. When our body burns fat for energy, we lose weight.
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For many individuals, a calorie deficit of 500 calories per day is enough for weight loss and is unlikely to affect our energy or hunger levels significantly. To make this calorie deficit, we need to know what our maintenance calories are.
Maintenance calories are exactly the number of calories our body requires to support energy expenditure [3]. We can use calorie calculators like the Body Weight Planner from the NIH (National Institute of Health). Such calculators estimate our maintenance calories based on our sex, weight, age, physical activity level, and height.
Though calorie calculators provide a reasonable idea of our maintenance calorie requirements, we can get a more precise number by tracking our calorie intake and weight for ten days.
While maintaining the same daily activity level, we should use a calorie tracking app to track our calories and weigh ourselves daily. For a precise result, use the same scale, at the same time of day, and wearing the same clothes (or without clothes).
Our weight may fluctuate day to day, but if our weight has otherwise remained stable over a period of 10 days, the average number of calories we consumed per day is a better representation of our maintenance calories. Divide the total number of calories we consumed for ten days by ten to find our average daily calorie intake.
We should subtract 500 calories from this number to determine our new daily intake goal for weight loss. For instance, if you find our maintenance calories to be 2,000 daily, our new daily calorie goal would be 1,500.
As we lose weight, our maintenance calories will decrease over time, and we will need to adjust our calorie intake based on our weight loss goals. Still, to ensure healthy weight loss and sufficient nutrient intake, women should not take fewer than 1,200 calories daily, and men no fewer than 1,500 calories in general [4].
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We can achieve a calorie deficit by consuming fewer calories or increasing our physical activity levels — or both.
That said, it may be more sustainable and more comfortable to create a calorie deficit through diet rather than exercise alone, as we may not have the energy, time, or motivation to exercise every day. Moreover, exercise doesn’t burn as many calories as most people believe.
In short, it may be simpler to consume 500 fewer calories every day than to burn this number of calories through workouts. Nonetheless, it’s still suggested to engage in aerobic and muscle-strengthening exercises to benefit overall health.
The PAGA (Physical Activity Guidelines for Americans) from the Department of HHS (Health and Human Services) suggested that adults do 75–150 minutes of vigorous-intensity activity or 150–300 minutes of moderate-intensity exercise, weekly.
Moderate-intensity exercise includes light bicycling and brisk walking, whereas examples of vigorous-intensity exercise are fast bicycling and jogging.
The guidelines also prescribe that adults do muscle-strengthening activities involving their major muscle groups — including the shoulders, back, chest, arms, and legs — at least 2 days every week.
Engaging in muscle-strengthening activities will help our body prioritize body fat loss rather than muscle mass.
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So how do you make a deficit of 3500 calories per week or 500 calories per day? We don’t have to starve ourselves with a juice fast or trendy diet. There are 3 healthy ways to make a calorie deficit for weight loss.
If we cut our portion sizes, we should cut back on snacking and opt for lower-calorie foods at mealtime; we’ll have fewer calories every day. If we reduce our caloric intake enough, we’ll create a calorie deficit large enough for weight loss.
The number of calories our body needs every day depends on our activity level. That includes the exercise we do every day and also our non-exercise physical movement. If we increase the number of calories our body needs but still consume the same number of calories from food, we’ll reach a calorie deficit.
Most successful dieters combine exercise and diet to lose weight. That means that they might take 250 fewer calories every day and then go for an hour brisk walk to burn an extra 250 calories. The calorie deficit would total 500 calories. If we created a similar plan for each day, we’d reach the 3500 calorie deficit needed for weight loss.
A calorie deficit occurs when we consume fewer calories than our body expands. A calorie deficit of 500 calories daily is adequate for sustainable and healthy weight loss.
Eliminating sugary drinks, consuming minimally processed foods like vegetables and fruits, and consuming home-cooked meals can help us reach a calorie deficit without calorie counting.