Written By Research & Development Specialist, Stefan Ianev
One of the biggest challenges we face when dieting, apart from dealing with the hunger, cravings, and low energy, is that after a few weeks the diet usually stops working and weight loss slows down. In other words, we adapt to all the positive benefits of the diet and start accumulating all the negatives.
That is just the bodies way of responding to the reduced energy intake. These defence mechanisms were put in place to prevent us from starving to death, and once upon a time they served us well.
The image below from Peos et al (1) illustrates some of the adaptive responses to caloric restriction.
Figure 1. Adaptive responses to caloric restriction (1).
The problem is that these days high density, high-calorie and highly palatable foods are so cheap and readily accessible in Western society that there is little chance of us starving to death. Unfortunately, the body hasn’t evolved and caught up with modern times yet, so we still have these aggressive, in-build mechanisms to defend against weight loss.
This is what makes weight loss and especially weight loss maintenance so challenging for most people. Possibly one of the best things you can do is not allowing yourself to become overweight in the first place, so you don’t have to deal with these challenges later on in life.
However, that is easier said than done because our defence mechanisms for preventing excess weight gain are far less aggressive than those defending again weight loss. That’s why it’s much easier for most people to gain weight that lose weight.
All hope is not lost though. Many people have lost weight and kept it off by following sensible and sustainable dietary strategies as I am going to outline in this article.
Before I present these strategies, which you might already be somewhat familiar with, I want to point out that they are all designed to SLOW down not speed up weight loss, at least in the short term. That is what makes them more sustainable in the long term.
The following strategies are presented in order of what I feel is most impactful to least impactful.
- Gradual Caloric Reduction
The more aggressively you cut calories at the start the faster the onset of metabolic adaptations will be and the quicker you will plateau. This is especially true for leaner individuals.
That’s because our metabolic rate, energy, sex hormones, and hunger are primarily regulated by the hormone leptin. Leptin senses energy availability from your body fat stores and the food that you consume.
The leaner someone is and the more they reduce calories the more leptin levels will tank. This means they are likely to experience a greater reduction in metabolic rate, low energy, extreme hunger, and lean muscle loss.
Long term this makes it extremely hard to stick to a diet, which is why all these 8-week challenges, or extreme 12-week transformations ultimately fail, even when people get results in the short term.
They do not enforce sustainable long-term dietary habits and individuals often blow out afterwards. The blowout inevitably leads to a panic attack and out of desperation these individuals will look for another quick fix. That is how the cycle of yo-yo dieting begins. I’ve seen this time and time again. People get stuck in this vicious cycle for years.
Had they been a bit more patient in the beginning and taken their time a bit more to get lean, and put in place sustainable long-term dietary habits, they would have achieved their goal much sooner.
When you start with a modest caloric deficit the onset of metabolic adaptations is much less severe, it gives you some room to move when you plateau, and it allows you to establish long-term sustainable eating habits. If you can’t see yourself following a particular diet for the rest of your life, it is not sustainable.
- Diet Breaks
Diet breaks involve a short period of 1-2 weeks where calories are brought back to maintenance. Studies have shown that diet breaks can increase weight loss efficiency by offsetting some of the negative metabolic adaptations in response to caloric restriction (2,3).
What we mean by increased weigh loss efficiency, is that you can achieve greater weight loss for the period that you are in a caloric deficit. That should not be confused with faster weight loss.
Although you might be loosing more weight while you are in a deficit by implementing diet breaks, you are also spending time not being a deficit at all, which can increase the total time required to hit your goal.
An example of this is the MATADOR study (2). Two groups were both placed on a 16-week isocaloric diet. One group dieted all the way through while the other group dieted two weeks on two weeks off. At the end, the group that dieted two weeks on and two weeks of lost significantly more weight (almost double) and had a much lower reduction in resting metabolic rate. Additionally, they maintained more of the weight lost after a six-month follow up.
However, you need to consider that it actually took them 32 weeks instead of 16 weeks to achieve those outcomes, so at the end it took longer even though they spend the same amount of time in a deficit.
If you are not time bound, implementing diet breaks is a great strategy to give you a psychological break from dieting, reverse some of the negative metabolic adaptations, and allow you to maintain a higher caloric intake verses continuous dieting.
I typically recommend a diet break every 6-8 weeks for most people. Leaner individuals meay need a diet break every 3-4 week while very overweight individuals that have a lot of weight to lose can get away with having a diet break every 12-16 weeks.
Although the research on refeeds is not as compelling as with diet breaks, we still have some research to suggest 2-3 day refeeds can work quite well for some individuals (4,5).
While diet break might actually reverse some of the negative metabolic adaptations to dieting, refeeds more likely just attenuate those adaptations. For example, if you normally crash after 4 weeks of dieting, by implementing refeeds, you might be able to extend the duration of your diet to 6-8 weeks before you need to take a full diet break.
This was illustrated in a study by Davoodi et al (5) when a group of participants were given a 3 day refeed every 11 days after the first 4 weeks of caloric restriction. Participants in the calorie shifting group not only attenuated but also partially reversed some of the negative metabolic adaptations.
Figure 2. Effects of caloric shifting verses continuous caloric restriction on resting metabolic rate (5).
Additionally, for some people refeeds helps them deal with the psychological aspect of dieting and make the process easier. For other people though it can break their rhythm and make it harder for them to get back on their diet. That is why refeeds need to be considered on a case by case basis.
Typically, I recommend a 2-3 day refeed every 5-12 days depending on how lean a client is and the magnitude of the deficit. Leaner clients or those on a more aggressive caloric restriction will need to refeed more often.
For example, when I start a comp prep phase and my body fat is sitting around 10 percent in the beginning, I can get away with refeeding about every 10-11 days. By the time I am sub 7 percent body fat, I need to refeed about every 4-5 days because my hunger starts getting out of control, and physically I start crashing.
For very overweight clients I generally don’t plan refeed days because they generally have enough body fat reserves to prevent them from crashing. I might give them a couple of free meals a week or a refeed day if they need a psychological break from dieting.
As you can see there is nothing magic about any of these strategies. They simply make the dieting process easier to adhere over the long-term and should be considered by anyone looking to achieve sustainable, long term results.
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- Peos JJ, Norton LE, Helms ER, Galpin AJ, Fournier P. Intermittent Dieting: Theoretical Considerations for the Athlete. Sports (Basel). 2019;7(1):22. Published 2019 Jan 16. doi:10.3390/sports7010022
- Byrne NM, Sainsbury A, King NA, Hills AP, Wood RE. Intermittent energy restriction improves weight loss efficiency in obese men: The MATADOR study. Int. J. Obes. 2017 doi: 10.1038/ijo.2017.206.
- Keogh JB, Pedersen E, Petersen KS, Clifton PM. Effects of intermittent compared to continuous energy restriction on short-term weight loss and long-term weight loss maintenance. Clin. Obes. 2014;4:150–156. doi: 10.1111/cob.12052.
- 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, 5, 19.
- Davoodi SH, Ajami M, Ayatollahi SA, Dowlatshahi K, Javedan G, Pazoki-Toroudi HR. Calorie shifting diet versus calorie restriction diet: a comparative clinical trial study. Int J Prev Med. 2014;5(4):447‐456.