TL;DR. In the long term, yes, but you still need to ensure you’re in a calorie deficit
What is a Diet Break?
No, it doesn’t involve Kit Kats.
Although it could if you wanted it to…
A diet break, otherwise known as a refeed is a planned and controlled increase in calories after a period of dieting.
By definition, if you’re dieting, you’ll be in a calorie deficit, so when you take a break, you should bring your calories up to maintenance for a period of time (one week is usually enough).
In the short term, taking a diet break might mean that your weight loss stalls for a period of time, but in the long term it can help with adherence, and help ensure that ou do actually acheive your final target weight.
How Do Diet Breaks Help With Fat Loss?
A diet break sounds counterintuitive if your goal is fat loss, but they can be beneficial from both a psychological and physiological perspective
Dieting is tough.
If anything it’s more difficult mentally than physically; week after week of calorie restriction can take its toll, particularly if you’re on very low calories.
Dieting means you need to be conscious of what you’re eating all day, everyday. Even if you’re on a flexible diet, calorie counting is still required to make sure you’re hitting your daily targets.
A break from this creates some mental headspace, and after weeks of dieting, the likelihood of overeating and undermining any results is highly unlikely
When you diet, you’ll go through a process of ‘adaptive thermogenesis’’, i.e. a reduction in metabolic rate as calories come down.
As this meta analysis finds;
Adaptive thermogenesis may help to partially explain the increasing difficulty experienced when weight loss plateaus despite low caloric intake”Trexler at al, 2014
This essentially means that your body will reduce the amount of calories it uses on a daily basis, as your body weight comes down, meaning you have to keep lowering calories if you want to lose more weight.
Here’s what that might look like hypothetically;
This is based on the TDEE calculations for a 40 year old female and shows that, as weight comes down, the amount of calories used (per day) also comes down.
A lighter body doesn’t need as much energy to ‘keep alive’, also moving a lighter body around (walking, running, picking up the Tv remote) requires less energy.
That’s right, contrary to popular belief, the lighter you are, the lower (or slower) yout metabolism will be.
This means that as you lose weight, you’ll need to keep lowering your calories if you want to continue the trajectory of weight loss that you’re currently on (or increase activity).
Otherwise this happens;
Note that the blue line (weight) plateaus as the TDEE (total daily energy expenditure) plateaus. This is because the made-up person in this scenario has ‘metabolically adapted’ to their new weight, causing their weight to plateau
Taking a diet break however could temporarily arrest this decline in metabolic rate; so while weight loss could stall temporarily, it may mean that a diet can be more sustainable, i.e. go on for longer.
In this scenario, calories are temporarily increased by 10% (from 1200 to 1320) for two weeks (week 15 and 16).
This is such a small increase that’s unlikely to significantly impact weight – if everything stayed equal it could, but it;s likely that TDEE will go up slightly to compensate for it. Even if weight did go up, it would only be by 0.25kg a small price to pay for the ability to continue dieting for several more weeks!
Also, who wouldn’t want to take a break from a diet?!
What Does the Science Say?
The scientific literature supports the use of diet breaks to overcome some of the effects of adaptive thermogenesis;
This sixteen week study of 51 obese men split the men into two groups. One used consistent energy restriction while the other used intermittent energy restriction (i.e diet breaks) across the period.
The intermittent energy restriction group lost more weight across the study period, but crucially also gained less weight when the study finished.
“intermittent [energy restriction]… resulted in weight loss (fat loss) without greater loss of FFM, attenuation of the reduction in [resting energy expenditure], and superior weight loss retention after 6 months, compared with an equivalent ‘dose’ of continuous [energy restriction]”
Byrne et al, 2017
How Often Should You Have Diet Break?
How often you should have a diet break depends on a few different factors
How Long Have You Been Dieting For?
Diet breaks should be used strategically and sparingly. Using them too often will mean that it takes you longer to reach your goal. Not using them at all could mean a heavy amount of adaptive thermogenesis and plateaus that you can’t overcome.
There are no right or wong answers as to how often you should take a diet break, your weight loss coach will be the best person to advise on when (based on your current rate of weight loss), but a good rule of thumb might be to take a week-long diet break every 8 weeks.
How Close Are you to your target?
If you’re close to your target, you may feel like you want to push through the final few weeks. But this could be a mistake. Weeks you’re dieting and constantly food-focused, weeks can feel like months so even a couple of days at maintenance calories could get you to your target more quickly.
Has progress stalled?
If progress has stalled it could simply be that your calories are too high and you need to bring them down. However if you’re already on very low calories (anything below the 1,200 mark) and progress is stalling then bringing caloies back up to maintenance (or just increasing by 10%) could help in a few different ways
- It can provide mental respite and allow you to go again hader after your diet break
- It can stabilise a reduction in REE (resting energy expenditure), meaning that when you do lower calories again, it could result in more weight loss
- It can allow you to do a little more exercise, which can increase TDEE, meaning that you could still be in a deficit because energy output is higher
Are you finding things difficult?
If you’re simply finding the diet hard from a physiological point of view, a break could be the difference in carrying on, and quitting altogether.
Long-term adherence is key with diets, so sticking to it at all costs is the only thing that matters, even if taking a break means it takes a little longer
Are There Any Other Options?
Slow dieing is an alternative, if the deficit is low enough then this may be enough to stave off any adaptive thermogenesis, although this is an unknown and dieting for long periods time may have other negative side effects.
Are Diet Breaks Similar To Cheat Days?
Technically, yes, although cheat meals imply a period of reverting to calorie maintenance or surplus that only lasts for a day; this likely isn’t enough to stabilise adaptive thermogenesis, although it doesn’t provide a physiological break, and if that’s all that’s needed to maintain diet adherence, then weekly ‘cheat meals’ could be a better strategy than week long diet breaks – although both could be combined.
Unless you have a hard target to hit a certain weight, such as a weigh-in for a sporting event, diet breaks make a lot of sense from an adherence point of view, but also as a strategy to keep REE as high as possible which could allow you to hit your target weight before you quit.
Metabolic adaptation to weight loss: implications for the athlete: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3943438/
Intermittent energy restriction improves weight loss efficiency in obese men: the MATADOR study: https://www.nature.com/articles/ijo2017206
Joe is an online weight loss coach and qualified personal trainer of 15 years who helps busy, professional men and women lose fat and build muscle.
Having a 9-5 desk-job, Joe understands the struggles of juggling a hectic life with trying to maintain a good physique.