The calorie deficit is the determining factor in weight loss, without it you physically can’t lose weight and it is a very important factor in fat loss. You must consume fewer calories than you burn or you will not lose weight. That said, all we must do is create a calorie deficit that is strong enough to cause a significant effect but not so strong that it can’t be maintained for a long enough time to cause the desired weight loss. A pound of fat contains roughly 3500 calories, burn 3500 calories and you’ve lost a pound of fat.
You could eat nothing at all but most could not sustain this for any length of time, on the other hand you could eat only fifty calories less than your maintenance intake but this would cause you to shed only five pounds in an entire year. As in all things, the key is moderation.
A suitable deficit for most people is 500 calories each day. This is easily sustainable for most and significant enough to cause a reduction in weight. This deficit will result in a loss of 0.45kg/1lb each week, which may not sound like much but that’s 23kg/52lbs in a year! 12 months is a short time for someone to completely transform their body. This is why it’s important to stay in it for the long haul, quick fixes sound great but can’t compare to the rewards earned from hard work and consistency.
A slightly more intense deficit is 1000 calories each day, this is sustainable for taller and heavier individuals as they have higher calorie needs than shorter, lighter individuals.
A tall 91kg/200lb man for example, would have daily needs of around 3000 calories each day, even with a deficit of 1000 calories, he would still be consuming a comfortable 2000 calories each day. This is far less suitable for a shorter lighter person, and more so for a shorter, lighter woman. A short 45kg/100lb woman will have calorie requirements of only 1400 calories each day. If she was to follow a 1000 calorie deficit, she would be consuming only 400 calories each day.
What would be an easily sustainable diet for one person, would be unsustainable and inadvisable for another, it’s all relative.
The most intense deficit shouldn’t exceed 1500 calories. This is pretty intense for anyone and should only be used to kickstart a diet before moving on to a more sustainable deficit.
A 1500 calorie deficit produces a fast rate of weight loss however it is important that the muscle preservation tactics mentioned later in this book are utilized when losing weight this quickly. If all aspects of this programme are used fully this deficit can take off 1.4kg/3lbs each week but don’t forget the importance of losing fat and not muscle. This isn’t to be used by shorter, lighter people.
Which is best?
This depends on you, it should be evident from the above paragraphs that there is not a one-size-fits-all answer. I advise a slow and steady approach of roughly 1% of your body weight each week or less.
If you are lean then I wouldn’t advise using aggressive deficits. Be sure to make use of the muscle preserving methods in this book, I encourage you to use every one of them.
The 1% Rule
It has been observed that the rate of maximal fat loss without muscle loss is around 1% of a person’s body weight per week. While there are always exceptions to the rule, I wouldn’t suggest straying far from it. If you’re around 68kg/150lbs, that means you can strive for 0.68kg/1.5lbs of fat loss per week without muscle loss. If you’re 136kg/300lbs then you can lose up to 1.4kg/3lbs per week with little risk of muscle loss. There is a big difference between the amount of fat that can be lost by people with different weights but the percentage is similar in most cases.
Choose a deficit to follow and stick to it for one whole week. You can always change it later.