Refeeding 101: Should We Periodize Energy Restriction?

Dieting, or rather, caloric restriction is a practice used by the general population to achieve weight (hopefully fat loss) and many types of athletes including but certainly not limited to professional bodybuilders (i.e., physique athletes).

It seems simple enough in theory, to limit calories going in by a certain amount each day until a goal weight or body composition is reached. However, human psychology and physiology is not keen on the idea of long-term calorie deficits.

Check out the NASM Nutrition Certification to learn more about the many methods of dieting for a healthier lifestyle. 

What is refeeding and who can benefit?

Refeeding is the practice of providing diet breaks or periods of consuming higher calories, either maintenance calories or slight caloric surpluses, during periods of calorie restriction or dieting. Theoretically, refeeding will help to combat weight loss plateaus and extend the weight loss phase via a few mechanisms. First, refeeds, especially refeeds specifically increasing carbohydrates will help to decrease muscle loss and help to reestablish higher levels of NEAT and EAT by refilling glycogen stores and providing more energy for activity.

Second, refeeds will help to boost metabolic rate by reducing cortisol levels and boosting leptin levels. Lastly, refeeding will provide a needed psychological break from caloric restriction which will allow the individual to stay consistent with their nutrition plan once dieting is reestablished (Peos et al., 2019).

Difference Between Refeed Days and Cheat Days

Refeeding days are not cheat days. A cheat day, although also a diet break strategy, generally allows the dieter to consume whatever they want in whatever quantity before resuming the diet. A refeed is a controlled increase in calories, generally up to maintenance calories or a slight surplus for a day or several days. Oftentimes a cheat day can result in negation of the prior calorie deficit, while a refeed should theoretically allow the dieter to take a break from the diet, without increases in fat mass (Chappell et al., 2018).

Refeeds can be appropriate for anyone adhering to a nutrition program which has them in a caloric deficit for weight loss purposes. This can include athletes attempting to cut weight, bodybuilders in a cut or in a prep for a show, or an individual trying to lose weight for health purpose, especially if progress has stalled.

How to implement a refeed

Refeeds are relatively simple to implement, if the dieter is tracking their calorie intake and/or intake of macronutrients precisely. The goal for all dieters for successful long-term fat loss is to retain fat free mass (mainly, we are referring to skeletal muscle), while decreasing fat mass preferentially. Moderate caloric deficits (300 to 500 kcal/day) may be more appropriate for leaner individuals (Ruiz-Castellano et al., 2021). Obese individuals can tolerate a caloric deficit of 500 to 1,000 kcal per day (Finkler et al., 2012) and their hormonal systems are less likely to resist fat loss (Finkler et al., 2012).

Baseline fat loss programs will differ depending on the starting weight and/or goal of the client. Overall, highly active individuals, or individuals with a high fat free mass, should consume 1.8 to 2.2 g/kg/day of protein, and at minimum 2 to 5 g/kg of carbohydrate per day (depending on sport and activity level) with the remaining calories coming from fats to achieve the desired caloric deficit. Less active individuals or obese individuals should aim for 1 to 1.5 g/kg of protein per day.

Carbohydrates can comprise about 40 percent of total calories and fats the rest of calorie intake. It is important to note that the exact ratio of carbohydrates to fats is less important for a less active person though a diet high in saturated fats and low in fiber come with health risks (Kim, 2020).

Once the baseline diet is set, refeed days can be programmed into the nutrition plan. Currently, there is insufficient research to support an exact protocol for when to implement a refeed day or how many days to implement, however there are some guiding principles that can help.

• There is some evidence that hormonal function (i.e., thyroid hormones and leptin concentrations) will normalize after a week of refeeding after a month of energy restriction. The same results are found with 10 days of energy restriction followed by 10 days of refeeding (Peos et al., 2019).

• Leaner individuals will be more resistant to fat loss both physiologically and psychologically. More frequent refeeding may be beneficial in this group (Campbell et al., 2020).

• Refeeding with preferential increase in carbohydrates is most effective at preventing losses of fat free mass, refilling glycogen stores, and providing more energy for physical activity (Trexler et al., 2014).

Sample Refeeding Schedules

It is important to note that refeeding can occur as single days in a week or a single day every few weeks. This table is just a sample based on several studies conducted in refeeding.

Are the benefits of refeeding real or all just hype?

Refeeding has become the subject of much interest in research for both overweight/obese individuals attempting weight loss and competitive athletes. Although more research is needed, there are a few studies that have validated some of the purported benefits of refeeding.

• Campbell et al. (2020) conducted a study looking at refeeding in resistance-trained men and women on an energy-restricted diet for 7 weeks, with 5 days of energy restriction followed by 5 days of refeeding. As compared to the control group, the refeeding group retained significantly more fat-free mass by the end of the diet period. This supports the idea that refeeding can help minimize muscle loss during a diet.

• Gripeteg et al. (2009) applied either a one-week or six-week refeed to obese patients who had recently adhered to a 12-week very low-calorie diet. The patients were then returned to a very low-calorie diet for another 40 weeks. The researchers determined that the group that was given a six-week diet break adhered to the diet much more closely in the subsequent 40 weeks of the diet than the group that was only given one week of refeeding. This study supports the idea that a prolonged refeed may improve long-term adherence to an energy-restricted diet.

• Peos et al. (2021) conducted a study placing a group of athletes in 12 weeks of energy restriction. The intervention group was given a 1-week diet break during the energy restriction period and evaluated for irritability, muscle endurance, fat mass, and mental alertness. The researchers determined that the diet break group had higher levels of muscle endurance, lower levels of irritability, and higher levels of mental alertness when compared to the control group not given a diet break. The diet break group did not experience any significant increase in fat mass during the diet break. This supports the idea that a periodic refeed will help maintain performance in athletes during periods of energy restriction.

A Word on Body Weight and MEtabolism

Body weight is regulated by genetics, environmental factors, hormonal factors, and human psychology. Historically, human beings were constantly faced with physical hardships. Food was sometimes scarce and required large caloric expenditure to acquire. Humans were constantly walking, moving, carrying objects- overall, humans were physically active.

The human metabolic systems evolved to adapt to environmental stressors, high caloric expenditure, and the intermittent availability of food. In other words, we are adapted to hold onto fat stores, and regain weight after a period of weight loss (Freese et al., 2018). Let’s examine the mechanism of how energy intake is used in the body.

In its simplest terms, body weight is governed by energy input minus energy expenditure or “calories in, calories out.” Energy input is the total sum of calories consumed in a day, whereas total daily energy expenditure (TDEE) is the sum of basal metabolic rate (BMR), non-exercise activity thermogenesis (NEAT), thermic effect of food (TEF), and exercise activity thermogenesis (EAT).

BMR is responsible for the highest caloric expenditure accounting for 60 to 70 percent of total calories burned per day. NEAT, or calories expended through just living life, accounts for another 15 percent. Thermic effect of food- calories used for digestive processes- accounts for another 10 percent of calories expended. Last, unless you are a competitive athlete or serious fitness enthusiast, EAT only accounts for 5 percent of TDEE (Summerfield, 2016).

Dieting for an extended period causes a phenomenon called metabolic adaptation. This is the process by which weight loss plateaus develop. Metabolic adaptation occurs when the body changes the “calories in, calories out” equation to preserve body weight or regain lost weight.

The body achieves this by increasing the rate of nutrient absorption, sending out appetite increasing hormones (i.e., ghrelin), increase in stress hormones promoting fat storage (i.e., cortisol), sometimes causing slight decreases in BMR (often because of loss of skeletal muscle), and increasing fatigue thereby reducing NEAT and EAT (Blomain et al., 2013). Metabolic adaptation can be very problematic for individuals seeking fat loss.

Read also: A Guide to Energy Balance

Conclusions

Refeeds may be a good idea for many dieters although more evidence is needed to make any official recommendations on whether to add refeeds to your dieting plans or what frequency/duration those refeeds should be. Current evidence does not seem to indicate that refeeding will derail a fat loss diet, which is great news for anyone wanting to try them.

The evidence seems to support the idea that refeeds can increase long-term adherence to a diet, help to normalize the hormone disturbances experienced during prolonged periods of weight loss and minimize muscle loss. They are worth a try, especially if you have experienced problems with any of these things in past diet attempts.

References

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Blomain, E. S., Dirhan, D. A., Valentino, M. A., Kim, G. W., & Waldman, S. A. (2013). Mechanisms of Weight Regain following Weight Loss. ISRN Obesity, 2013, 1–7. https://doi.org/10.1155/2013/210524

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Freese, J., Klement, R. J., Ruiz-Núñez, B., Schwarz, S., & Lötzerich, H. (2018). The sedentary (r)evolution: Have we lost our metabolic flexibility? F1000Research, 6. https://doi.org/10.12688/f1000research.12724.2

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Gripeteg, L., Torgerson, J., Karlsson, J., & Lindroos, A. K. (2009). Prolonged refeeding improves weight maintenance after weight loss with very-low-energy diets. British Journal of Nutrition, 103(1), 141–148. https://doi.org/10.1017/s0007114509991474

Kim, J. Y. (2020). Optimal diet strategies for weight loss and weight loss maintenance. Journal of Obesity & Metabolic Syndrome, 30(1). https://doi.org/10.7570/jomes20065

Peos, J. J., Helms, E. R., Fournier, P. A., Krieger, J., & Sainsbury, A. (2021). A 1-week diet break improves muscle endurance during an intermittent dieting regime in adult athletes: A pre-specified secondary analysis of the ICECAP trial. PloS One, 16(2), e0247292. https://doi.org/10.1371/journal.pone.0247292

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