Consistent with the current study, recent findings indicate that slow weight loss, as recommended by current guidelines, worldwide, is not a priority over rapid weight loss. Purcell et al. in a clinical trial studied the effect of weight loss rate and weight management. Their results showed that in the long-term, with rapid weight loss (450 to 800 Kcal/day) than gradual weight loss (500 kcal less than the daily requirement), the weight loss is faster and more stable. The researchers suggested that the limited carbohydrate intake of very-low-calorie diets might promote greater satiety and less food intake by inducing ketosis. Losing weight quickly may also motivate participants to persist with their diet and achieve better results (29).
Any movement counts. The numbers are daunting: The 2018 Physical Activity Guidelines for Americans suggest a minimum of 150 minutes (2.5 hour) of moderate-intensity aerobic activity a week (walking briskly, playing doubles tennis, raking leaves), or 75 minutes (one hour, 15 minutes) of vigorous-intensity activity (running, a strenuous fitness class, carrying groceries up stairs), as well as muscle-strengthening activities (resistance training and weightlifting) two days a week. But if you want to lose weight, work up to 300 minutes of moderate-intensity activity a week, or 150 minutes of vigorous-intensity activity. “But doing something just a few minutes a day to get started has benefits,” said Piercy. “So parking farther away when you’re running errands, getting up from our desks and going down the hall instead of sending an email -- those are things people can start incorporating into their daily lives now that may be a little easier than saying, ‘Oh my gosh, I have to figure out how to fit 2.5 hours of activity into my week.” If you are starting from zero physical activity, Dr. Jakicic suggests taking a 10-minute walk five times a week, shooting for 50 minutes a week, and building on from there once it becomes habit.
Everyone is different. How quickly you burn calories when you are not physically active can be very different from other people based on your specific genes, biology, and past. While scientists know that there are 3,500 calories in one pound, simply eating 500 fewer calories every day for a week (or 3,500 fewer calories in a week) does not always end in losing exactly one pound.