Can aggressive fat loss be safe and effective?
Ever wondered if the sprint could be as effective as the marathon when it comes to fat loss?
There's often debate around whether slow and steady wins the race or if an aggressive approach could get you over the finish line faster.
After interviewing Dr. Bill Campbell (renowned professor of Exercise Science and Director of the Performance & Physique Enhancement Laboratory at the University of South Florida,) for an upcoming interview on the podcast, I've got some intriguing science to share with you.
How does a mere 2-week fat loss phase sound?
Not an uncontrolled crash diet but a scientifically-backed way to lose 5 pounds in 2 weeks with little to no loss in muscle.
One of Dr. Campbell's recent studies examined a rapid fat-loss diet over two weeks versus a moderate fat-loss diet spanning seven weeks in 19 resistance-trained women.
The aim was to investigate their effects on body composition, resting metabolic rate (RMR), and hunger.
In the aggressive fat loss group, participants slashed their calorie intake by a whopping 50% while upping their protein intake to 1.1 g/lb (2.5 g/kg) of body weight. Let's say you're 200 lb and burn 2,800 calories per day. You would consume 1,400 calories to be in a 50% deficit, losing 2.8 lb per week, so this is quite aggressive.
On the flip side, the moderate fat loss group cut their calories by 25% and raised their protein intake to 0.8 g/lb (1.8 g/kg) of body weight. In this case, you would consume 2,100 calories to be in a 25% deficit, losing only 1 lb per week (64% slower weight loss).
Each group followed the same resistance training program three times a week.
The results were intriguing...
Both groups lost similar amounts of body fat, but the rapid group also saw more lean body mass loss.
However, and this is important, the loss of lean body mass in the rapid group was primarily due to water and glycogen depletion rather than actual muscle tissue loss.
In other words, as soon as they started eating at maintenance, they would see this lean mass return rapidly.
As far as the body fat loss, let's take a moment to think about this.
In only 2 weeks, the rapid fat loss group lost the same weight it took 7 weeks for the moderate fat loss group without losing muscle mass!
In terms of metabolism, the rapid fat loss group saw a greater reduction in RMR (-80 kcal/day vs -21 kcal/day) and also experienced higher levels of hunger compared to the moderate fat loss group.
This also makes sense because you're eating fewer calories. But again, you're doing it for only 2 weeks, not 7.
So, what's the conclusion?
A 2-week rapid fat loss diet can be just as effective for fat loss as a 7-week moderate fat loss diet.
It appears that actual muscle loss is negligible, and while there is a reduction in metabolism and increase in hunger (as you would expect on any diet), it's over extremely quickly (only two weeks).
This aggressive approach could be used intermittently, interspersed with diet breaks or refeeds to mitigate some of these drawbacks and enhance long-term adherence.
Why am I sharing this?
Because sometimes the best tool is the most surprising one, and I think it's critical you're aware of every possible way to lose fat.
However, if you have never gone through a proper fat loss phase (with resistance training and high enough protein, while tracking and managing biofeedback like hunger), 99% of the time we would NOT take the above approach for two main reasons:
You usually have more weight to lose (on average around 20-30 pounds)
You haven't yet developed the skills of living in a calorie deficit and making sustainable food choices for energy balance, macronutrients, and micronutrients
In that case, being in a deficit that causes body weight loss of around 0.5-0.75% is usually more sustainable and will take around 10-16 weeks, sometimes longer with diet breaks or refeeds.
But then once you've arrived at your "healthy lean" level of weight and have been lifting for at least 6 months (newbie gains are behind you), the aggressive fat loss approach above is an option for a quick cut.
However, there is an interesting middle ground to consider. What if you go all-out aggressive for 2 weeks, then dial it back to a moderate rate of loss? This might even "feel" like a diet break initially, and you could get the entire fat loss phase over in say 6-8 weeks instead of 12.
In other words, as always, it depends on what YOU prefer, can adhere to, and help you reach your goal as fast as possible without losing muscle mass. "Get in and get out" on your terms.
Last point: this is NOT a "crash" diet where you just restrict foods, your protein is too low, you may not be resistance training and your weight plummets while taking significant muscle mass with it, followed by ravenous hunger and a binge.
Let me know if this gets the creative juices flowing for your next fat loss phase!
And if you're a lifter (new or advanced) who wants to shed some stubborn body fat to improve both your health and physique, reach out to me to chat about your options.
I'll help you get to your goals in the fastest, most efficient, most sustainable way so you can get back to building muscle while also "looking like you lift."