Why Your Low-Calorie Diet Stopped Working

Starvation Mode Isn’t Real, but Metabolic Adaptation Is

A continual calorie deficit can eventually stop working. If your fat loss has stalled and you’re eating less than a crack addict, check this out.

As a trainer and nutrition coach, one of the most common things I hear is, “I’ve only been eating 1100 calories a day for the past two years, and I still can’t shed any fat!”

Anywhere around 1000-1200 calories is a steep deficit for most average-height, active people. Eating that little for that long with nothing to show for it would be confusing and disheartening.

We like to think in a very input/output mindset. Most calorie-counters think they’ll be able to lose as much weight as they want if they stay within a certain caloric range. When that doesn’t happen, those same people conclude that their metabolism has slowed down because of age or genetics.

These beliefs are usually false. Fat loss doesn’t occur linearly because our bodies are adaptive. Their metabolisms simply adapted to their current calorie intakes.

Many coaches describe this phenomenon as “starvation mode,” but that’s not quite right. (I used this term, too, before learning what was actually going on.) Let’s examine why that happens and what you can do about it.

Here’s What Happens When Your Deficit Lasts Too Long

When you’ve been eating in a deficit for a prolonged period, your body will adjust at the hormonal level. According to Eric Trexler, Ph.D. (1), the effects of weight loss and caloric restriction have a widespread impact on hormone profiles, which include:

  • A reduction in thyroid hormone, which leads to a decrease in metabolic rate.
  • A reduction in leptin, which leads to a decrease in metabolic rate and increased hunger.
  • Increases in ghrelin, which will increase hunger.
  • Decreases in insulin, which increases hunger and threatens muscle retention.
  • Decreases in testosterone, which threatens muscle retention and reproductive health in men.
  • Decreases in estradiol, which threatens bone health and reproductive health in women.
  • Increases in cortisol, which leads to water retention, blunted leptin activity, and possibly threatens muscle retention.

A prolonged period of calorie restriction is not just a metabolic adaptation, but according to Trexler, it’s a “multifaceted set of adaptations that involves regulation of energy expenditure, appetite, reproductive function, and the balance between anabolism and catabolism.” (1)

So What’s The Solution?

Once your body has adapted to a state of caloric restriction, the only options for continued fat loss would be to restrict calories further or increase energy expenditure. However, there’s a point where you can’t do either safely or even expect positive returns.

Problem is, there’s no distinct line in the sand for the maximum amount of time you should spend in a caloric deficit. For most, a fat loss phase is going to be a 12-week cycle, but depending on how much weight you have to lose and how steep of a caloric deficit you’re in, that figure can have some variance.

So, what can be done to get the body back to homeostasis and potentially set it up for a successful fat-loss phase?

The first step is to increase your caloric intake back to a maintenance level. That number would be the equivalent to your TDEE (total daily energy expenditure). You can find that by simply Googling “TDEE Calculator” and entering your height, age, weight, and activity level.

If you’ve spent a long time in a steep deficit (over 6 months and over a 500-calorie daily deficit), spend 6-8 weeks at a maintenance level to bring your body back to a place where your hormones can reregulate and you can restore your metabolic function.

Even if you have a large amount of weight to lose, a small diet break can help both physically and mentally. However, if you’re in the midst of a long-term fat loss journey, when you go into brief maintenance phases, your new maintenance level calories won’t be the same as when you started. Remember, as you lose weight, your maintenance level (TDEE) comes down along with it.

Big Huge Tip

I’ve coached quite a few people who’ve spent over a year in extreme caloric restriction before coming to me. One of the scariest things I’ve had them do is increase their calories with a big emphasis on protein. This strategy is usually met with some resistance, but once they trust the process, it’s amazing how their bodies begin to change.

If you’re in a similar situation, try a macronutrient ratio that starts with 40% protein, then break up the fats and carbs based on your preferences. That may take some tweaking, but I recommend a higher ratio of carbs for those who are hungrier and a higher ratio of fats for those who aren’t as hungry.

Carbohydrate sources tend to have more volume. If you struggle to consume maintenance-level calories, opt for a tablespoon of olive oil or coconut oil in a protein shake to fit your calories in from fat while not filling you up too much.

What Next?

After you’ve spent some time back at maintenance level, restart the fat loss process by slowly cutting calories again. This sounds counterintuitive, but the goal is to eat as much as possible while still losing fat.

Additionally, all planned calorie reductions should come from carbohydrate and fat sources. Keep your focus on maintaining a high-protein intake to ensure you retain as much muscle as possible.

The most important takeaway? A fat loss phase needs to be just that – a phase. You shouldn’t be spending months or years in a deficit. The return on investment diminishes greatly after a certain point.

If you’ve spent over 16 weeks in a deficit of 500 calories or more and you’re no longer experiencing positive physique changes, it’s time to seriously consider a short-term diet break or a longer-term maintenance phase. Fat loss can improve your health, but prolonged periods of caloric restriction can have harmful metabolic and hormonal implications.

If you’re just starting your fat-loss phase, you might also consider spending five days in a deficit and two days at maintenance. Details here: The Non-Linear Fat-Loss Diet for Lifters.

Make any nutrition strategy work better:



  1. Trexler, E. (2019, March 26). The Metabolic Adaptation Manual: Problems, Solutions, And Life After Weight Loss. Stronger By Science.

Thoughts on restricted calories during the week, and higher (maintenance or within 4-500 over) on weekends? Should have the ability to do this longer term before body adapts? What about the zig zag method, 2 deficits followed by 1 maintenance day, or something along those lines? I am down 14lbs in 7 weeks and feel I am highly motivated and doing a sustainable plan, but think I need to lose at least as much again to fully lean out. I have a history of killing my metabolism with chronically adjusting lower, so I am trying to stay out ahead of it and also make progress.

Like this plan? The Non-Linear Diet for Lifters


Nice! I missed this article but this is pretty much what I have been doing! I feel like its easy to restrict during the weekdays with work and busy schedule, and is much more satisfying on the weekends to not have (as much) a restriction. Thanks for the link!


You bet!

This is an interesting question and something I would have to research further to give you a definitive response. However, I tend to look at caloric intake from a daily average perspective. Having fluctuations from weekdays to weekends could theoretically help stave off that adaptation as an advanced dieting technique (similar to carb cycling). However, from a longer term perspective, if you are in a deficit from a daily average standpoint over a significant period of time you may still want to consider a diet break or maintenance phase. With that said, the best indicator for when to make that switch is if aesthetic results are stalling, strength is declining, and energy levels begin to drop. Your body will let you know when its time.

Hope this helps.

1 Like

From Dr. Schoenfeld:

Thus, diet breaks do not appear to induce improvements in body composition or metabolic rate in comparison with continuous energy restriction over six weeks of dieting, but may be employed for those who desire a short-term break from an energy-restricted diet without fear of fat regain.

The accumulating evidence does not support claims of a benefit to diet breaks on body comp

The Effects of Intermittent Diet Breaks during 25% Energy Restriction on Body Composition and…
The purpose of this study was to examine the effects of intermittent versus continuous energy restriction on body composition, resting metabolic rate, and eating behaviors in resistance-trained…

Does this suggest that “diet break” effectiveness is dependent upon the length of time of the diet and the length of time of the “break”?

Thank you

I see your study and counter with another study that says the opposite. Studies are fun!

  1. Campbell BI et al. Intermittent energy restriction attenuates the loss of fat-free mass in resistance-trained individuals. A randomized controlled trial. J Funct Morphol Kinesiol. 2020 Mar 8;5(1):19. PubMed .

This was another study cited in the reference article:

Pardue A, Trexler ET, Sprod LK. Case Study: Unfavorable But Transient Physiological Changes During Contest Preparation in a Drug-Free Male Bodybuilder. Int J Sport Nutr Exerc Metab. 2017 Dec;27(6):550-559. doi: 10.1123/ijsnem.2017-0064. Epub 2017 Aug 3. PMID: 28770669.

I think worrying about body composition changes over a 1-2 week diet break is naive. Unless you plan to completely let the rails off for the entirety of it, or actively binge every day then it’s not going to make much of a difference for the average person. Those stipulations are irrelevant for the more stringent trainee as they still plan it out when and what they’re gonna eat. That “rest” from dieting works fantastically as you plan to return to lower calories, increasing your adherence to allow you to prolong your cut further. Even if you did mess up and manage to gain a pound or two over the break, that’s largely outweighed by the ability to continue deeper into weight loss without feeling like shit.


Anyone remember the ABCDE diet?


Still a big fan of the idea there. Enjoy the articles on it too!

This is an interesting article with things I never thought about. I have been stuck in a plateau after losing 25 pounds 6 months ago, and it seems pretty counterintuitive to eat more. I have been more active as well, but struggling to find balance in my diet. I have very low calorie days and days i eat off the chain! I will try this strategy and increase my calories for a few months and see how it lands. Thanks for the insight.