A caloric deficit is a situation where the body is using more energy than it is taking in. Fat loss is synonymous with a caloric deficit. If you are in a caloric deficit, you will lose fat. If you are losing fat, you are in a caloric deficit. A caloric deficit can be implemented via two methods – decreasing the amount of energy into the body or increasing the energy output by the body. Simply put, eating less and/or moving more.
Now, fat loss programs is not necessarily as simple as this. There are plenty of other factors that can come into play, however fat loss cannot occur if a caloric deficit is not in place.
The important thing to know here, is that your body burns most of its energy without you even knowing.
The energy your body uses, or your ‘metabolism’ can be broken down into five components:
- Basal metabolic rate (BMR): this is the minimum amount of energy needed just to maintain vital functions – the amount of energy you’d use if you were to sleep indefinitely
- Resting metabolic rate (RMR): is BMR plus the energy required for important metabolic tasks like maintaining your body temperature and digestion
- Thermic effect of food (TEF): the energy required to digest food, which means that the activity of eating actually burns calories. Protein has the highest thermic effect, followed by carbohydrates then fat
- Exercise activity (EA): the energy used for purposeful exercise
- Non-exercise activity thermogenesis (NEAT): is all the energy used for everyday movement, such as walking around the workplace, making dinner and fidgeting
As you can see, there are many factors that go into ‘calorie burning’ and depending on how active you are during the day at home or at work (your NEAT levels), exercise activity may be, or close to, the smallest factor in energy output. This being said, many people push for cardio in the gym weeks on end to lose weight, when it doesn’t greatly affect their overall output.
It is much easier to manipulate the amount of food going in. Rather than doing an hour of moderate intensity exercise every day, simply eat 500 calories less. It’s easier and does the same job. Reducing calories cannot consistently be used to continue losing weight. At some point it will not be optimal for healthy functioning, but for most individuals, reducing the amount of food they’re eating will be the best first step
In summary, cardio is not completely necessary to lose fat, but can be a useful tool, especially after a prolonged period of dieting and calories have already been lowered within a reasonable range.