Does the idea of Dieting for months at a time fill you with dread?
How about the idea of just a 2 week diet?
Now before you begin thinking I’m about to sell you on some wonder pill or ‘magic’ diet consisting of Celery Soup and Coconut Oil, let me explain….
For a long-time in the realm of bodybuilding there has been this notion of a “Refeed”.
Typically it is a spell of time increasing calorie intake above dieting levels, for many this has been provided courtesy of a “Cheat Meal” or for those a little more balls-to-the-wall a “Cheat Day”.
The idea stemmed from a mechanism commonly misunderstood and then referred to incorrectly as “Starvation Mode”. It’s an idea with proven scientific merit, but executed a little poorly.
Basically the body gets less calories so it begins slowing you down to balance out the equation a little more. This part is certainly true.
You diet, your energy goes down and so you move less. Your Training intensity drops, you’re eating less food so don’t have to burn as many calories digesting it, your core temperature lowers and your body just generally becomes more efficient at using the calories it has for daily function (this is known as Adaptive Thermogenesis).
Now this is a concern when dieting to lose bodyweight, but only after sticking to the diet itself. Because 99 times out of 100, a failed diet doesn’t come down to this, it comes down to the extra calories we start sticking in our face when we get bored of it.
The best way to reduce the negative effects of dieting? Simply eating more calories (especially from Carbs).
So how about the idea of just restricting calories for 2 weeks and then spending 2 weeks maintaining that weight loss? Essentially a ‘Diet Break’.
For most that would certainly seem like an attractive option, you get the emotional joy of only ‘dieting’ for 14 days at a time and then the biological advantage of coming out of “Starvation Mode” (picture me saying that sarcastically with double quotation signs like Dr Evil) for a period of time after.
Great theory, so how does it work in practice?
Luckily some fine folks in Australia decided to test this out for themselves.
The study was set out like this, 47 Obese subjects split down the middle, half were subjected to 16 weeks of calories at 67% of what would be required to maintain their bodyweight. The other half spent 2 weeks doing this, followed by 2 weeks with calories increased to maintain the new weight for a total of 30 weeks (16 weeks dieting, 14 weeks not dieting).
The Results were as follows…
“The weight loss was greater for INT (14.1±5.6 vs 9.1±2.9 kg;P<0.001). INT had greater FM loss (12.3±4.8 vs 8.0±4.2 kg; P<0.01), but FFM loss was similar (INT: 1.8±1.6 vs CON: 1.2±2.5 kg; P=0.4). Mean weight change during the 7 × 2-week INT energy balance blocks was minimal (0.0±0.3 kg). While reduction in absolute REE did not differ between groups (INT: -502±481 vs CON: −624±557 kJ d−1; P=0.5), after adjusting for changes in body composition, it was significantly lower in INT (INT: −360±502 vs CON: −749±498 kJ d−1; P<0.05).”
(Byrne et al., 2017)
What does this all mean?
Well “Greater weight and fat loss was achieved with Intermittent Energy Restriction.”
Spending 2 weeks dieting followed by 2 week ‘rest periods’ seemed to reduce compensatory metabolic responses (it slowed down the Resting Metabolic Rate less) and, in turn, improved weight loss efficiency.
Alongside this the group doing the ‘2 On, 2 Off’ Diet maintained their weight loss to a much greater extent in the 6 month follow up.
Speculatively this could be due to a combination of factors :
Time spent learning to maintain bodyweight
A lower reduction in Resting Metabolic Rate
Lowered negative effects of dieting (Reduced hunger? Higher NEAT levels?)
So what can we learn from this?
Well if you’re willing to spend a little longer losing the weight and think you could stick to calorie restriction better knowing you only have to do it for 2 weeks at a time then this might be worth trying.
However, remember this isn’t a 2 week diet followed by a 2 week binge, this is 2 weeks at calories needed to lose weight followed by 2 weeks at calories to maintain that weight loss.
For those that would prefer, and more importantly are able to, grin and bear it for a shorter period of time to get to their goals, stay tuned for my next post…
Byrne, N., Sainsbury, A., King, N., Hills, A. and Wood, R. (2017). Intermittent energy restriction improves weight loss efficiency in obese men: the MATADOR study. International Journal of Obesity.