Pablo here again! We are zooming through February, but it's a great time to check in on your resolutions for this year. How are you doing so far? Are you going strong? Did you make an initial investment? Do you need more motivation?
If fat loss is your goal, fasting has benefits that can give you the edge you need to accelerate your results. The science behind fasting is pretty straightforward: When you don’t eat, your body enters ketosis, shifting from burning carbs to burning fat for energy, which speeds up fat loss.
For those fasting, ketosis typically begins after the body exhausts its glycogen stores, usually within 12 to 24 hours of starting a fast.
Understanding the timing of this metabolic shift can help you optimize your fasting windows and maximize your fat-burning potential.
What Is Ketosis?
Ketosis is a metabolic state in which the body burns fat for fuel instead of carbohydrates.
Typically, the body relies on glucose from carbs for energy, but when carbohydrate intake is drastically reduced—such as during fasting or a low-carb diet—glucose levels drop and the liver starts breaking down fats into a chemical called ketones (also called ketone bodies).
These ketones then become the primary energy source for the body. Research shows that ketosis can enhance fat burning, improve mental clarity, and even support muscle preservation during periods of calorie restriction. Dr. Sebi said it best!
“When you fast, the body goes into maintenance mode, self-healing.” -Dr. Sebi
When Does Ketosis Start When Fasting?
For most people, ketosis typically begins around 12 to 24 hours into a fast, although the timing varies from person to person based on factors like individual metabolism, activity level, and your diet prior to fasting. Those who have already adapted to a low-carb or keto diet may enter ketosis more quickly.
How to Get Into Ketosis Faster
One of the most effective ways to speed up ketosis is to reduce your carbohydrate intake drastically, typically to less than 20 to 50 grams per day.
Incorporating intermittent fasting (IF) can also speed up the process, as fasting depletes glycogen stores more rapidly. Additionally, increasing physical activity, particularly high-intensity exercise, helps burn off remaining glycogen stores faster, prompting the body to enter ketosis.
Why Entering Ketosis Might Take Longer
Various factors influence how the body processes carbohydrates and burns fat. For instance, if glycogen stores are particularly full due to a high-carb diet before starting a fast or low-carb regimen, it can take longer for the body to use it all up.
Additionally, individual metabolic differences like insulin sensitivity, age, and activity level play a role. If you’ve been following a high-carb or standard diet, it may take 2 to 4 days or more to fully enter ketosis, as the body needs time to adjust.
Other factors, such as stress or lack of sleep, can increase cortisol levels, which may hinder the transition and even result in an increase in stress belly fat. Patience and consistency are key during this adjustment phase, and maintaining a strict low-carb, high-fat diet, along with regular physical activity, can help expedite the process.
How Does Ketosis Promote Fat Loss?
The process of ketosis naturally encourages the body to burn stored fat for fuel, which helps accelerate weight loss. An October 2016 study in The Journal of Clinical Endocrinology and Metabolism found that a very low-calorie ketogenic diet resulted in weight loss primarily due to fat loss, while muscle mass and strength stayed relatively the same.
In addition to losing weight, ketosis has anti-inflammatory effects that support overall metabolic health, according to a December 2021 study in Frontiers in Medicine. This reduction in inflammation can help alleviate conditions like metabolic syndrome, insulin resistance, and other obesity-related health issues.
And by improving insulin sensitivity, ketosis helps the body manage blood sugar levels more effectively, preventing excess sugar from being stored as fat, per a July 2023 study in Nutrients.
How to Fast for Fat Loss
There are various types of fasting protocols, but intermittent fasting is one of the most popular and effective approaches for fat loss. It typically involves cycles of eating and fasting, such as the 16/8 method (16 hours of fasting followed by an 8-hour eating window), which allows the body to enter a fat-burning state.
During fasting, in addition to the body breaking down fat for energy, there’s an increase in growth hormone production, which helps preserve muscle mass, boosts fat metabolism, and promotes fat loss, according to a landmark study in The Journal of Clinical Investigation.
For maximum fat loss, it’s important to ensure that during eating periods, you consume nutrient-dense, whole foods—rich in healthy fats, nutrients, and low-glycemic carbohydrates—to support the body’s needs and avoid overeating.
Ultimately, the key to successful fasting for fat loss is consistency and choosing a fasting window that fits your lifestyle. Over time, fasting helps regulate hunger hormones, reduce appetite, and improve fat oxidation, making it easier to maintain a healthy weight and lose fat.
Who Should Not Fast?
While fasting can offer numerous health benefits, it’s not suitable for everyone. Certain individuals should avoid fasting or consult a healthcare professional before beginning any fasting regimen. These include:
- Individuals with a history of eating disorders, such as anorexia or bulimia, should avoid fasting, as it can exacerbate an unhealthy relationship with food and may trigger disordered eating patterns.
- Women who are pregnant or breastfeeding have increased nutritional demands to support both the mother and child. Fasting can deprive the body of essential nutrients, potentially affecting fetal development or milk supply.
- People with conditions such as type 1 diabetes, heart disease, or severe low blood pressure should be cautious when considering fasting.
- Growing children and adolescents have higher caloric needs to support development, and fasting may hinder their growth and overall health.
- Those who experience chronic fatigue, weakened immune systems, or other health conditions may find that fasting exacerbates symptoms.
For anyone considering fasting, consult with a healthcare professional, especially if you have underlying health issues or specific health concerns. Fasting is not a one-size-fits-all approach, and proper guidance is key to ensuring safety and effectiveness.
Until next time,
Pablo
