If we want to achieve true fat loss, we need to be expending more calories than we are taking in. If we are not in this energy burning state, we cannot lose fat by definition. Your body does not want to use up your fat stores unless you absolutely have to. A diet is basically controlled starvation against yourself. Over a long enough time period your body will do whatever it takes to hold onto that fat. That is why, the leaner we get, the harder it is to lose more and more body fat. You are going against all of your survival instincts.
When most people think of fat loss they think of maximizing the calorie burn. It makes sense right? If you want to lose weight, then you should want to maximize each session and choose a form of exercise that burns the most calories. The answer to that is more complex.
Yes it is true. If the goal is purely fat loss, then focusing all your efforts on doing cardio will burn the most calories in the shortest amount of time. There is a cost to that however. If all you did was cardio in a caloric deficit, over time your body adapts. It will start burning through your muscle and prioritize holding onto that fat. I’m going to assume this is not the goal you had in mind. If all you do is burn through your muscle, then you’ll just look like a smaller, skinnier version of yourself. I’d imagine what you really want is to be a leaner, muscular, more toned version of yourself right? Then we want to preserve muscle. Long bouts of cardio don’t require much muscle mass so there is no reason to keep it on, whereas strength training provides the perfect stimulus for retaining muscle. This is why you see a lot of people start a diet and lose a lot of weight, and then their fat loss just stalls even though they are doing insane amounts of cardio for a long duration.
LISS, HIIT, and NEAT
There are 3 tools you can implement to create a caloric deficit:
Increase NEAT – for some, just increasing their step count is the easiest transition to creating a bigger deficit. Instead of having to make extra time to run on the hamster wheel for 30 minutes, you may rather increase your step count by 2,000 steps. So let’s say you average 10,000 steps a day normally. Try bumping it up 2,000 a day and see if that pushes the scale down more. If not, keep adding 1,000 till it does.
Low Intensity Steady State Cardio – Some people like to just get it out of the way, rather than trying to find a bunch of time throughout the day to go for 10 minute walks. For this method, I recommend starting out with 2-3 days of LISS for 30 minutes (or 300 calories burned a session)
HIIT – If you’ve added 2-3 days of LISS and/or want to mix it up with a different style of cardio try incorporating HIIT (15-20 minutes of 5-6, 20-30 second sprints). Again, less is better. Once any given cardio session builds up to 35-40 minutes, I’d recommend adding a new day of cardio so the session isn’t so long. The benefits of HIIT are it will be better for maintaining muscle mass than LISS because the intensity is higher. The downside however, is it is significantly more stress on the body so be careful not to overdo this. Being in a deficit, plus adding in regular cardio AND HIIT is just adding more and more stress to the body on top of your daily life.
Be sure to check out my article on If Sprints are a Good Form of Cardio.
Above all else, make sure you are weight training 2-3 times a week. Not only does it provide the optimal signal for maintaining your current muscle mass, but as you put on more muscle, it will INCREASE your metabolism. Cardio on the other hand, slows down your metabolism. It will help mitigate any muscle loss signals that cardio might be providing and still burn calories.