Thursday, September 18, 2014

Rapid weight loss: is 3.5 kg a week possible?

How to lose the biggest amount of weight in the least time possible is, and has always been one of the main topics in the health and fitness society. One of the recent diet hypes is “Lose 3.5 kg in a Week Diet”, but is it actually possible?

If we are talking about weight loss, then yes, it is easily possible. But if we are talking about fat loss that’s a different issue; let’s delve into reality behind fat loss and how much of it is possible and realistic per week or per day.

People often mix between weight loss and fat loss, but they are not the same. Diet extremes result in mainly water and lean tissue losses rather than fat, because sudden deprivation and lack of source of energy forces the body to use its muscle tissue for energy, along with that a lot of water is gone. Any water weight loss is both temporary and illusionary.


Despite the fact that major health and scientific bodies recommend fat loss rate at 0.5 to 1 kg per week to promote health; lots of people –for whatever personal reason- still want the fastest way possible. Now back to our question…


Is losing 3.5 kg per week (i.e. 0.5 kg fat per day) possible?

In order to lose 0.5 kg per day you need to create a 3,500 kcal deficit diet each day, or by restricting calories and increasing caloric expenditure totaling 3,500 Kcal, and for already lean individuals; this not physiologically possible, and there is no science to support that it is; because “dietary restriction which exceeds the limited capability of the fat stores to compensate for the energy deficiency results in an immediate decrease in the fat free mass (i.e. muscle tissue)”.


However, for overweight and obese people it could happen “on theory”. Again “on theoretical” calculation overweight and obese individuals could lose as far as 0.5 kg fat a day with extreme caloric restriction and intense training program, but most likely it won’t happen for most of them, due to other factors involving such as:

  • Gender:- women find it harder to lose fat than men due to body muscle mass and hormones).
  • Previous level of fitness:- persons who are new to the training -especially cardio- find faster results in burning fat compared to persons with already good adapted cardiovascular system.*
  • Previous attempt of dieting:- a.k.a: yo-yo effect; which makes the body stubborn toward fat burning.

* Cardiovascular capacity is crucial for fat burning; since fat burning depends on the abundance and delivery of oxygen to tissues.


So what’s the sum up?

Even though losing 0.5 kg a day “could” be possible for some individuals under certain circumstances, we don’t recommend it. It doesn't teach good life style habits, and could jeopardize your health and level of mental focus, in addition to higher chances of gaining flabby skin afterward.


2 kg per week could be achieved depending on your current basal and actual metabolic rates, to take action; know how to calculate your daily caloric needs and caloric expenditure from exercising (which is something you should seriously consider to speed up fat loss, maintain muscle mass and promote health). 

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