It most certainly is not. In fact, multiple studies have indicated that dropping fat quickly is detrimental to long-term health. Highly restrictive crash diets tend to lead to more future weight gain shortly after completion, leaving you worse off than you were before.
For example, a close relative of mine used to exercise and make major dietary alterations to hit their goal as soon as possible. What started out as a goal of 15 pounds in three weeks turned into 20 and 30 because following each bout of rapid cutting, they would get fatter.
The ideal pace to cut digits from the scale is one-to-two pounds per week. So, if dropping 15 is the goal, budgeting 7-15 weeks is reasonable, safe, and sustainable.
Sustainable fat loss is achieved through lifestyle changes. Drinking more water, limiting processed foods, and eating more fruits, vegetables, healthy fats, and lean proteins are the way to go. Increasing activity can also help you burn calories. For many, simply making these changes will be enough. When you hit a sticking point and the scale isn’t moving, simply cut 250-500 calories per day or boost activity levels.
Doing all of this will allow you to keep weight off, and more importantly, lead to lower cholesterol, inflammation, and the risk of chronic illness.
The next time you think about dropping a few, think about sustainability, not speed. When it comes to reaching weight goals, slow and steady wins the race.