Keto Carb Refeeds: Necessary Or Unnecessary?

Carb refeeds are a popular strategy for those following a keto diet. They involve a short period of time, usually a day, where a person intentionally consumes more carbohydrates than usual. This kicks the body out of ketosis, which is the purpose of the refeed. Carb refeeds are believed to help break a weight loss stall, improve hormonal balance, enhance muscle growth, and increase energy expenditure and leptin concentration. However, they are not recommended for beginners as they can be challenging and may awaken carb cravings. There is also limited scientific research on the effectiveness of carb refeeds, and they may not be suitable for those with a history of disordered eating.

Carb refeeds can help with weight loss plateaus

Carb refeeds can be an effective strategy to overcome weight loss plateaus. When your body enters a prolonged state of calorie deficit, it can lead to a decrease in leptin levels. Leptin is a crucial hormone that signals to your brain that you have adequate fat stores, helping to regulate appetite and encourage calorie burning. However, when leptin levels drop, your body interprets it as entering a period of calorie deprivation, triggering a survival mechanism called adaptive thermogenesis. This process involves various hormonal changes that ultimately lead to a reduction in energy expenditure and an increase in food cravings, making it challenging to continue losing weight.

Carb refeeds can help counteract this issue by providing a temporary boost in calorie intake, primarily through carbohydrates, which have a more significant impact on leptin levels compared to fats or proteins. By strategically increasing your carbohydrate consumption, either daily or weekly, you can elevate leptin levels and reset your body's fat-burning process. This approach is particularly effective for individuals who have been on a low-carb or calorie-restricted diet for an extended period and have reached a weight loss plateau.

It is important to note that the effectiveness of carb refeeds varies from person to person, and there is limited scientific research specifically on this topic. Additionally, carb refeeds should be implemented in a controlled manner to avoid overeating or triggering strong carb cravings. It is recommended to consult a healthcare professional to determine if and how carb refeeds can be incorporated into your diet plan.

They can improve hormonal balance

Carb refeeds can be beneficial for improving hormonal balance. This is mainly due to the effect they have on leptin levels. Leptin is a hormone that communicates to your brain how much fat you have stored. When you follow a low-carb diet, your leptin levels decrease, which signals to your brain that you are running low on energy resources. As a result, your brain responds by trying to conserve energy and increasing food cravings. Carb refeeds can help boost leptin levels, which in turn can regulate appetite, encourage calorie burning, and improve overall hormonal balance.

Additionally, carb refeeds can also positively impact other hormones. Insulin, for example, is a hormone that plays a crucial role in thyroid function, bone growth, brain function, and the balance of other hormones such as estrogen and testosterone. Chronically low insulin levels, which can occur with long-term very low-carb diets, can have negative health effects. By incorporating carb refeeds, you can help maintain optimal insulin sensitivity and avoid the negative consequences of both high and low insulin levels.

The impact of carb refeeds on hormonal balance is particularly notable for women. Premenopausal women's bodies are especially sensitive to changes in leptin levels, and leptin also plays a role in regulating reproductive and immune systems. As a result, carb refeeds can help women achieve optimal hormonal balance and overall health.

Furthermore, carb refeeds can be strategically timed to coincide with hormonal fluctuations throughout the menstrual cycle. For example, carb cycling strategies may involve increasing carb intake during the luteal phase (days 19-20 of the cycle) or during the first few days of the period, when leptin levels tend to dip. This approach can potentially provide a boost to leptin levels when they are naturally lower.

It is important to note that while carb refeeds can improve hormonal balance, they should be implemented in a controlled manner. The goal is to strike a balance and maintain optimal insulin and leptin sensitivity. Overdoing carb refeeds or not returning to a keto diet afterward can negate the potential benefits. Additionally, carb refeeds may not be suitable for everyone, especially individuals who are new to keto or have certain health conditions. It is always advisable to consult with a healthcare professional before making significant dietary changes.

Carb refeeds can enhance muscle growth

Additionally, the practice of carb refeeding can help preserve muscle mass during weight loss. A study by Campbell et al. (2020) found that a 5-day low-calorie phase followed by a 2-day refeed resulted in greater fat loss, muscle mass retention, and maintenance of resting metabolic rate compared to a continuous diet.

Furthermore, refeeding can also have psychological benefits, making dieting easier to stick to. This can be especially helpful for those experiencing weight-loss plateaus or other signs of hormone dysregulation, such as menstrual irregularities and sleep disruptions.

However, it is important to note that the effectiveness of carb refeeds may vary from person to person, and there is limited direct scientific research specifically on "refeed days." The benefits of carb refeeds may also be influenced by individual factors such as activity levels, genetics, and biomarkers.

They may increase energy expenditure

Carb refeeds may increase energy expenditure by boosting leptin levels. Leptin is a hormone that signals to the brain that there is sufficient energy available in the body. When leptin levels are low, the body may respond by reducing energy expenditure and increasing hunger and appetite. By increasing carb intake, carb refeeds can boost leptin levels and potentially increase energy expenditure.

Leptin is often referred to as the "satiation hormone," but it is more accurate to think of it as a starvation sensor. Its main role is to communicate to the brain how much fat (stored energy) is available in the body. When leptin levels drop, it signals to the hypothalamus that there may be an energy shortage, triggering a process called adaptive thermogenesis. This process involves decreasing energy expenditure and increasing hunger and appetite to conserve energy.

Carb refeeds can help counteract this effect by boosting leptin levels. Carbohydrates, especially when consumed in excess, lead to an increase in leptin levels. By periodically increasing carb intake, individuals can potentially prevent the decrease in energy expenditure associated with low leptin levels.

Additionally, carb refeeds can enhance athletic performance, which may indirectly contribute to increased energy expenditure. Carbohydrates provide fuel for the muscles in the form of glycogen. By replenishing glycogen stores, individuals may be able to train harder and improve their performance, leading to a potential increase in overall energy expenditure.

It is important to note that the evidence for the effectiveness of carb refeeds is mostly anecdotal, and more research is needed to fully understand their impact on energy expenditure. Additionally, carb refeeds may not be suitable for everyone, especially individuals with a history of disordered eating or certain health conditions. It is always advisable to consult with a healthcare professional before making significant changes to your diet.

Carb refeeds can boost leptin concentration

Carb refeeds can be an effective strategy to minimise the negative hormonal or metabolic effects of long-term low-carbohydrate intake. Leptin is a hormone released by fat cells that communicates to the brain how much fat (stored energy) the body has. When leptin levels are low, the brain responds by trying to save more energy. This can lead to food cravings, mood swings, low energy, and stalled weight loss efforts.

Carbohydrates have a positive impact on leptin levels. High-glycemic carbs (e.g. sugar) may be the reason for increased leptin levels after meals. An increase in carb intake has been shown to boost leptin levels and alleviate the negative symptoms associated with low leptin levels.

Leptin levels rise in response to eating carbohydrates, specifically 4-48 hours after a carb refeed. Therefore, carb refeeds can be a valuable tool to boost leptin levels and metabolism. However, it is important to note that chronically elevated hormone levels can lead to reduced sensitivity in brain receptors, so carb refeeds should be cycled and not used daily.

Additionally, not all carbs are created equal. Unrefined, complex carbohydrates from whole-food sources are the best choice for a carb refeed as they replenish glycogen, balance insulin sensitivity, and provide valuable nutrients.

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