What Works Best: Aggressive or Moderate Dieting?

Constant vs. Progressive Diets for Fat Loss

Drop calories quickly or lower them gradually? What works best for fat loss? Researchers tried to find out. Here’s what happened.

When it’s time to lean up, what approach do you take? There are three popular options. For, let’s say, 8 weeks, do you…

  1. Drop calories immediately to the lowest, safest level and suck it up?
  2. Drop calories just a little below maintenance intake and wait patiently?
  3. Drop calories a bit every couple of weeks, working your way down to an aggressive deficit?

With the first approach, you probably expect to lose more fat and uncover those abs faster. With the second, more relaxed approach, you don’t expect rapid results, but it beats being really hungry all the time. The third approach is somewhere in the middle.

What works best? That’s what researchers wanted to find out in this study. Spoiler alert: They did not find out. Instead, they learned something else.

The Study

Remember, this study kinda “failed,” so I’ll be quick with the summary:

Researchers divided 14 weight-lifting women into two groups with either an aggressive or moderate caloric deficit. Both groups logged their meals using a macro-counting app and followed the same training program.

  1. The Aggressive Dieting Group: Right off the bat, these women dropped their calories low (25 kcals per kg of FFM or fat-free mass) and were told to stay there for 8 weeks. This is called “constant” dieting.
  2. The Moderate Dieting Group: These women started their diets with a modest calorie drop (40 kcals/kg FFM), lowered cals every two weeks, and finished the final two weeks like group one: 25 kcals/kg FFM. This is called “progressive” dieting.

Dr. Bill Campbell, in his Body By Science newsletter, kindly broke that down using a hypothetical woman weighing 145 pounds with 22% body fat:

  • If she were in the aggressive/constant group, she’d consume 1300 calories every day.
  • If she were in the moderate/progressive group, she’d consume 2320 calories in the first two weeks, drop roughly 250 calories every couple of weeks, and finish the final two weeks at 1300 daily calories.

Which Group Had the Best Results?

You’re probably thinking that the aggressive dieters lost the most fat. After all, they consumed far fewer calories over the 8-week period.

Nope. The moderate/progressive group lost a bit MORE fat (-3.75 pounds) than the aggressive/constant group (-2.6 pounds).

How’d That Happen?

Well, the aggressive dieters ate more than they were supposed to. Duh! The moderate dieters, however, stuck to their plans.

In fact, the aggressive dieters wound up consuming more calories overall than the moderate dieters. We can’t say they “failed” because they did lose fat, but they simply weren’t able to stick to their prescribed calorie intakes over the long haul, as their food logs showed.

Now, we could blame the researchers. Those calorie restrictions were just too strict, especially for experienced females lifting weights four times a week and doing cardio six days a week, as they did in the study.

Or we could blame the… no, let’s not. The women did the best they could, given the ridiculously low calories. When I asked my wife, an experienced lifter, about eating 1300 calories a day, she said, “That amount of calories is for children.”

How to Use This Info

You’ve heard this expression: The best training program is the one you can do consistently. Well, it’s the same with diet. Choose whatever “flavor” of calorie deficit is the most sustainable. For most people, that’s a 300-500 calorie deficit (with a high protein intake for best results).

Also, recent research into non-linear diet strategies looks promising. In a nutshell, these plans have you eating low calories for 5 days, then bumping back up to maintenance for 2 days. Fat loss is a bit faster than a traditional linear approach, and muscle mass and resting metabolic rate are better maintained. You can read all the details here: The Non-Linear Diet for Lifters.

The metabolism-boosting, award winning protein:




  1. Vargas-Molina, et al. “Efficacy of progressive versus severe energy restriction on body composition and strength in concurrent trained women,” Eur J Appl Physiol, 2023 doi: 10.1007/s00421-023-05158-8.
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