As I explained in an earlier blog post, the human metabolism is highly plastic, and prone to both up- and down-regulation. In most cases, down-regulation of the metabolism will occur as a result of chronic dieting. Diet breaks can be used as a tool to combat some of this metabolic down-regulation that results from eating in a calorie deficit.
The goal of this article to give you a clearer understanding of: -
What a diet break is
What a diet break involves
Who should use diet breaks
How often you should utilise a diet break
What is a Diet Break?
From the outset much of the information I am providing here comes courtesy of Lyle McDonald who has written extensively on the diet break.
Now a diet break can occur at 2 main junctures: -
1) In a planned fashion, whereby an individual has finished a diet, or a phase of dieting, and want to have a period of maintenance at a certain body weight/body fat.
2) In an un-planned fashion, whereby life circumstances makes dieting impossible. This usually occurs during a holiday period.
Now, let’s understand what is going on from a physiological perspective when we go on a diet.
Firstly, our metabolism starts to slow as we lose weight
On top of the slightly reduced metabolism from weight loss, our body adapts our metabolism further by reducing our spontaneous activity (NEAT) and thereby reducing our daily calorie expenditure (adaptive thermogenesis)
Thyroid output decreases
Leptin output decreases
Ghrelin output increases - increasing our hunger and appetite
By raising calories, we seek to normalise these hormones and allow the metabolism to recover.
A diet break can also serve psychological needs too:
“by breaking your dieting efforts up into smaller chunks, while maintaining control over your eating in the long-term, you are less likely to lose control or go off of your diet completely” (McDonald, 2005)
What Does a Diet Break Involve?
Carbohydrate intake needs to be increased to at least 100g per day, which is crucial to the up-regulation of thyroid hormone.
Calories need to be increased to maintenance levels - this is simply the amount of calories required to maintain your current body weight/fat levels
Adjusting calories up to maintenance levels can be done fast or slow. A fast approach would see you increase calorie intake within 1-2 days. A fast approach can be problematic for some because: -
It can be easy to lose control of food intake
People can report gastric upset due to the increase quantity of foods (and different types of food)
Some people experience some bloating and water retention from the additional carbohydrates (particularly if they were following a very low carbohydrate diet)
Therefore, for some individuals, a slower approach to increasing calories can be beneficial. A slow approach would see you increase calories over the span of a week.
Who Would Benefit From Using Diet Breaks? How Often Should They Be Utilised?
The basic answer to this is ‘anyone who is currently on a diet’. However, the frequency of their use should be altered depending on a dieter’s specific situation. Essentially, the leaner an individual is, the more frequently you should use a diet break.
McDonald’s (2005) recommendations are as follows: -
“Category 1” Dieters (Males <15%/Females <24%) - Every 4-6 Weeks
“Category 2” Dieters (Males 16-25%/Females 25-34%) - Every 6-12 Weeks
“Category 3” Dieters (Males 26%+/Females 35%+) - Every 12-16 Weeks
These recommendations are very general guides, but give some indication of how long you should be in a calorie deficit for. One of the biggest mistakes I see people make is maintain a low calorie intake chronically. There are huge benefits to increasing calories periodically to allow your body to recover.
In Summary: -
Chronically dieting can have a raft of negative impacts on your body
Taking 1-2 week diet breaks can have both physiological and psychological benefits
Diet Breaks involve bring calorie intake back to maintenance levels and increasing carbohydrates to over 100g per day
Diet breaks should be utilised more frequently the leaner you become