When you’re in a calorie deficit, you’re essentially underfeeding your body which results in your body adapting by burning fewer calories and making you hungrier. This is known as metabolic adaptation which makes sense from a survival/evolutionary perspective.
Your body tries to adapt during this scarcity of food so that you can survive! But in our world today; where food is abundant and the goal is to lose as much fat as possible – this is a huge pain/ inconvenience and makes it extremely difficult to continue burning fat
The rate of fat loss naturally slows down as you reduce your overall body fat percentage due to something known as metabolic adaptation. A study by Columbia University found that your energy expenditure can drop by up to 28% after just 5-8 weeks of dieting! To put this into perspective – a female who burns 2000 calories a day could be burning just 1440 calories after just a few months of dieting!! (This is on the more extreme spectrum but it just highlights how much of a hit your metabolism can take when dieting)
So What Exactly is a Diet Break?
A diet break is a dieting protocol which is intended to negate the metabolic adaptations that take place in your body and to give you a mental ‘break’ from the struggles of dieting.
THE MATADOR STUDY
Byrne et al conducted a study with 51 obese men; the researchers separated them into 2 groups:
Group 1: 33% calorie deficit for 16 weeks
Group 2: 33% calorie deficit with 2 week diet breaks at maintenance for a total of 30 weeks
Group 2 (with the diet breaks) ended up losing 50% more fat, no extra muscle loss and a much less metabolic slowdown. (50% less metabolic slowdown than group 1 which basically means they had significantly ‘faster’ metabolisms).
So, with a diet break, not only do you lose more fat, you can also spare your metabolism!
The researchers also did a 6 month follow up after this study and the diet group break maintained 80-90% more fat loss in the 6 month follow up, and the group without the diet breaks regained significantly more weight after the diet ended
*study limitations/ pointers
This study was implemented on obese men so we can’t say the same results would be found for lean individuals or females BUT from my own personal experience, my experience with my online coaching clients and from observing other fitness/nutrition coaches in the industry, the same results of diet breaks do apply to other populations too
Physiological Reasons to Implement a Diet Break
A short period of eating at maintenance calories has the potential to reverse some negative metabolic adaptations that can occur from being in a calorie deficit. It allows your hunger hormones (leptin and ghrelin) to be restored to normal levels which = less hunger and cravings, more energy, improved mood, better performance in the gym
image source: https://www.weightwatchers.com/nz/food/hormones-appetite-and-weight
Psychological Reasons To Implement a Diet Break
Having a mental break from your rock solid diet commitment is massively beneficial to your long-term diet success. The mental toughness that is required; especially towards the back end of a diet can slowly start to deteriorate and willpower naturally decreases. Having a mental break from dieting allows you to relax a little and then go back into a dieting phase with significantly more motivation and drive to keep going.
How To Implement A Diet Break?
- Raise calories to your new maintenance levels (important to remember that your metabolism adapts as you lose body fat – which means that the calories you ate to maintain your weight at the start of your diet will not stay the same)
- Eat at your maintenance calories for anywhere from 7 days to 2 weeks and even longer in some cases (completely dependent on your goals, time frame, metabolic adaptions, hormones etc)
- Research has shown that diet breaks (2-3 days+) work more favourably in terms of your hormones being restored in comparison to 1 day refeeds or cheat meals
- You want to prioritise increasing your calories from CARBS and back down your proteins and fats slightly. Research shows that carbs are the macro that most positively impact your leptin levels so it makes logical sense to get the majority of your calories from carbs during a diet break
- Cut down your cardio (a good guideline is to cut cardio in half for the duration of your diet break)
- The more severe the calorie deficit, the more frequently diet breaks will need to be implemented
- Often times, the more lean you are, the more diet breaks you’ll need
Downsides to Diet Breaks
- Much longer dieting periods to include time for diet breaks
- A diet break isn’t a card to eat whatever you want and forget calories and macros. Diet breaks usually involve bringing calories up to maintenance levels and so this might only be an extra 300~ calories or so for some people (which might not even feel like a diet ‘break’
- If you’re dieting for a specific event or if you have a set time scale to lose a certain amount of fat, diet breaks may not support this.
I hope this helps you understand the term diet break a little better and be sure to let me know if you implement one into your dieting period!
Columbia University https://www.ncbi.nlm.nih.gov/pubmed/18842775
The Matador study https://www.ncbi.nlm.nih.gov/pubmed/28925405