Losing 2 kg in 4 days is possible (plus some considerations)

A recent study has just come out to determine if a rapid fat mass reduction can be achieved in 4 days by combining calorie restriction and exercise.

The goal was to create an energy deficit of 5000 kcal/day.

General protocol

15 overweight men (100 kg) went through five experimental phases:

• Phase 1: Initial assessment and normal life (1 week and 4 days).
• Phase 2: Exercise + calorie restriction for 4 days
• Phase 3: Reduced exercise + diet control for 3 days.
• Phase 4: Analysis after 4 weeks
• Phase 5: Analysis 1 year later.

phase 2

Diet: Intake of 3.2 kcal/kg of body weight per day (320 kcal) coming from only one energy source:

• GROUP 1: Whey protein isolate in water + micronutrients (no fats).
• GROUP 2: Sucrose in water + micronutrients (no fats).

Exercise: Walking 8 hours on foot + arm cycle ergometer (45 min).

The goal was to create a 5000 kcal/day energy deficit.

phase 3

• Diet: Intake appropriate to their weight from a balanced diet (approx 2200 kcal)
• Exercise: Walk at least 10000 steps daily (no upper limit)

After finishing this phase, direct intervention with the subject stops and they are advised to keep exercising and dieting until the 4th week, although it’s not mandatory or necessary.

results

• After phase 2: Average loss of 2.1 kg and 1% fat relative to initial weight (current weight = 97.8 kg)
• After phase 3: Average loss of 2.8 kg and 1.6% fat relative to initial weight (current weight = 97.2 kg).
• After phase 4: Average loss of 3.8 kg and 2% fat relative to initial weight (current weight = 96.2 kg)
• After phase 5: Average loss of 1.9 kg and 2% fat relative to initial weight (current weight = 98.1 kg)

After phase 2 (the most intense), biochemical parameters like serum glucose, leptin, insulin, total cholesterol, LDL, and triglycerides decreased; while free fatty acids (FFA) and cortisol increased.

study conclusion

According to the researchers, effects were similar in both groups, and a clinically relevant reduction in fat mass can be achieved in overweight men in just 4 days.

personal conclusion

If you only read the study summary, you miss a lot of data. It turns out that of the two diet intervention groups, the one that took only sucrose regained weight more easily than the one that took protein. In fact, after phase 5, the real results were:

• Group 1: Lost an average of 0.8 kg
• Group 2: Lost an average of almost 4 kg.

It’s clear how the protein intervention seems to encourage a higher protein intake in their later diet (without intervention). So, those diets are more filling and allow fewer daily calories, enabling greater weight loss.

In my opinion, subjects in group 1 should rethink the success of their weight loss program, since a 1% reduction in 1 year is basically failing. On the other hand, cramming so much exercise with calorie restriction in just 1 week causes poor adherence to a non-sedentary lifestyle and exercise.

My personal take is that steady and balanced is better than intense and unbalanced. Obviously, results take longer to show up, but they’ll be more meaningful (you could lose up to 4 kg in 3 months).

sources

• Calbet et al. (2014). A time-efficient reduction of fat mass in 4 days with exercise and caloric restriction. Scand J Med Sci Sports. [Epub ahead of print].