Intermittent fasting has been gaining popularity as a weight loss and health improvement strategy, but what exactly is it and is it right for you? As a personal trainer in San Mateo, I want to provide you with the information you need to make an informed decision about incorporating intermittent fasting into your lifestyle.

First, let’s define intermittent fasting. It is an eating pattern where you alternate periods of eating with periods of not eating or significantly reduce your calorie intake. There are several different methods of intermittent fasting, including the 16/8 method, where you fast for 16 hours and eat during an 8-hour window, and the 5:2 diet, where you eat normally for 5 days and restrict calorie intake for 2 non-consecutive days.

One of the main benefits of intermittent fasting is weight loss. Research has shown that it can lead to a decrease in body weight, body fat, and waist circumference (Johnstone et al., 2007; Harvie et al., 2011; Fontana et al., 2010). This is likely due to the fact that when you fast, your body is forced to burn stored fat for energy instead of relying on the food you just ate. In addition, intermittent fasting has been found to improve insulin sensitivity, which can lead to better blood sugar control and a reduced risk of type 2 diabetes (Harvie et al., 2011; Mattson et al., 2014).

Intermittent fasting has also been found to have positive effects on heart health. Studies have shown that it can lower blood pressure and cholesterol levels (Heilbronn et al., 2005; Varady et al., 2009). In addition, it has been found to improve endothelial function, which is a measure of how well your blood vessels are able to dilate and supply blood to your organs (Hoddy et al., 2014).

Intermittent fasting may also have anti-inflammatory and anti-aging effects. Research has found that it can decrease inflammation markers in the body (Moro et al., 2016) and increase the production of a protein called brain-derived neurotrophic factor (BDNF), which plays a role in the growth and survival of nerve cells (Mattson et al., 2004). This may help protect against cognitive decline and neurodegenerative diseases.

While there are many potential benefits to intermittent fasting, it’s important to note that it may not be right for everyone. If you have a history of disordered eating, it’s best to avoid intermittent fasting and speak with a healthcare professional before making any changes to your eating pattern. In addition, it is important to note that it may cause negative effects in some individuals. Here are a few examples:

    • Hunger and cravings: One of the most common negative effects of intermittent fasting is feelings of hunger and cravings. This can be particularly challenging during the fasting period and may make it difficult for some people to stick to the eating pattern long-term.
    • Low energy levels: Intermittent fasting may also lead to low energy levels, particularly during the fasting period. This can make it difficult to engage in physical activity or complete daily tasks.
    • Nutrient deficiencies: If not done correctly, intermittent fasting can lead to nutrient deficiencies. For example, if an individual is only eating during a narrow window of time, they may not be getting enough vitamins and minerals from their food.
    • Hormonal imbalances: Intermittent fasting may disrupt menstrual cycles and lead to hormonal imbalances in some women. Research has found that it may increase levels of the stress hormone cortisol and decrease levels of the hormone leptin, which regulates appetite and metabolism (Moran et al., 2016).
    • Disordered eating: For individuals with a history of disordered eating, intermittent fasting may trigger unhealthy eating behaviors and exacerbate existing issues.

It’s important to consider these negative effects and to consult with a healthcare professional before starting any new eating pattern. Additionally, if you experience any negative effects while practicing intermittent fasting, it’s best to stop and seek guidance from a medical professional.

At Holly Roser Fitness, we believe in using evidence-based strategies to help our clients achieve their health and fitness goals. If you’re interested in learning more about weight loss strategy, we’re here to support you and provide you with the guidance you need to do so safely and effectively.


Fontana, L., Meyer, T. E., Klein, S., & Holloszy, J. O. (2010). Long-term calorie restriction is highly effective in reducing the risk for atherosclerosis in humans. PloS one, 5(6), e11201.nHarvie, M., Pegington, M., Mattson, M. P., Frystyk, J., Dillon, B., Evans, G., …

Similar Posts