For most people, weight loss is a simple matter of mathematics- consume less food than your body expends to create a calorie deficit to trigger the body into burning its own fat. Though the tried and true formula sounds easy enough to execute, many employ alternative methods in hopes of finding that magic equation for weight loss.

According to Alex Thomas, founder of Sport Nutrition Australia, one of the most common mistakes people make when trying to lose weight is to cut out entire food groups from their diet. “Unless you have a particular health condition that means that you can’t eat certain foods, variety is important,” he says.

Though it can be helpful for those with conditions such as diabetes and celiac disease to cut down on carbs or sugary fruits, according to the Mayo Clinic, the emphasis should be on consuming healthy sources of carbohydrates rather than eliminating them from one’s diet.

Thomas says a well-rounded diet is the first step toward achieving a healthy body weight, which means a balanced source of nutrients. “Your body thrives on both macro and micronutrients, and when you cut out an entire food group, it can have side effects when it comes to your health.”

This same principle applies to eliminating any part of the food pyramid. Sugars and fats are equally important energy sources, vitamins and minerals and should be consumed in moderation rather than avoided.

Fad diets that eliminate or focus on specific foods cycle in and out of popularity; experts believe the tried and trusted method of tracking what you eat and creating a calorie deficit is the best approach to cutting body fat and losing weight.

“The best way to improve your health markers and to lose weight is to be at a calorie deficit,” says Thomas.

A calorie deficit happens when you input less into your body than your output. Eating fewer calories than needed in daily activities and exercise creates an environment for the body to burn more fat. To track calorie deficit, we need to identify Basal metabolic rate (BMR), which indicates the number of calories to determine the calories required for our bodies to function; this number is influenced by weight, height, gender and age.

BMR formula for men: BMR = 88.362 + (13.397 x weight in kg) + (4.799 x height in cm) – (5.677 x age in years)

BMR formula for women: BMR = 447.593 + (9.247 x weight in kg) + (3.098 x height in cm) – (4.330 x age in years)

Input vs Output
Thomas says putting less into your body than what you burn is a simple way to determine if you will lose weight.

He advises keeping track of calories consumed with particular attention paid to a shift in intake on cheat days or weekends where one might be eating and drinking more alcohol. He says one way to track calories accurately is to be consistent with what you eat. “It is actually a lot easier to measure your input if you are consistent with what you are eating and drinking.”

Tracking output, on the other hand, he says, is a bit tricker.

There are more variables, including BMR, exercise, and non-exercise activities such as fidgeting, sleep or hydration. One way to start creating and tracking a deficiency is to stay consistent. “A good start for this would be to plan on doing around 8000 steps a day, three to four resistance training sessions, eat similar food each day and be mindful of your non-exercise activity.”

Basal metabolic rate

Your BMR will slow down as you reach different stages in your weight loss journey. “This is because our bodies don’t really like to change and will fight to stay as they are. It is also because your body doesn’t require as much energy to fuel it when you lose weight,” says Thomas.

A good indicator of a shift in the body is how much we engage in non-exercise movements. “This is because you can be more tired when you first start on a calorie deficit plan, so as a result, you may not be fidgeting as much, pacing when you are on the phone, getting up as much to get water or have a break.”

As research indicates, fat loss depends solely on energy expenditure, regardless of how it’s achieved. “Independently of the method for weight loss, the negative energy balance alone is responsible for weight reduction,” according to the study. Therefore, cutting out certain groups may help shed weight, but it is likely due to eating less overall rather than because you’re avoiding certain foods.