If you are aiming to lose weight over time, you might decide to place yourself in a daily 500 calorie deficit. Now this would equate to a 3500 calorie deficit per week meaning the outcome would likely be 1lbs weight loss a week.
Unfortunately we cannot pick and choose where this weight is lost from, be it fat stores, muscle or water. Where you lose it from will depend on a whole host of factors including gender, age, hormones, neurological determinants and more.
So if you were to maintain the above mentioned 3500 calorie deficit over the course of a year then it would be quite reasonable to expect around 52lbs weight loss, right? In which case, if this theory is accurate over time, you one could then expect to eventually wither away to nothing, no? Despite still consuming 1500 calorie (a 500 calorie deficit on the previous 2000 calorie intake)?? Really?
Of course not, a 500 calorie deficit will only facilitate 1lbs weight loss for so long otherwise we would continue to lose weight over time, and we don’t. Instead we need to adjust the deficit accordingly to accommodate the reduction in total mass, potential losses in metabolically active tissue, slight reductions in metabolic rate and so on.
What happens instead is a slowing down of metabolic rate to compensate for the lower calorie intake. I liken this to a bank account e.g. only paying £400 into an account and wanting to spend £800 each month will eventually prompt a call from the bank manager asserting that you should slow the rate of outgoings to suit the rate of income. As a result, no matter the deficit, eventually the number of calories our body will expend will start to fall.
To keep losing weight at the rate you started 1-2lbs a week, you’re going to have to reduce calories even further. You may well have to drop the calories by another 100 or so a month in and so on. This is why starting on too lower calories is futile to long term weight loss, some MANtra Diet Reset won’t let you do!
You also have neurological and hormonal changes that occur when you lose weight because the body really doesn’t like losing weight, it reverts back to the neolithic fears of starvation, commonly termed ‘starvation mode’, but more appropriately termed adaptive thermogenesis.
Fact is, if you want to enter a 500 calorie deficit to lose weight, great, so long as the diet is nutritionally dense and balanced, and assuming you don’t place yourself in a calorie deficit that means your margin for further calorie reduction (which is inevitable) is nil… then consistent, lasting weight loss is achievable. However, jump indiscriminately into a hyper calorie deficit of 1000 calorie at a BMR of 1800 calorie (the calories just to maintain heart rate, upright posture etc) and expect the body to slow things right down in compensation, and for any weight loss to be very short lived!