Does fasting increase testosterone?

While there are mixed opinions on this, recent research has highlighted that fasting may decrease testosterone levels. An 8-week study of resistance-trained males compared normal eating patterns to a time-restricted eating window. It aimed to determine the effects of intermittent fasting when combined with resistance-trained individuals. While the time-restricted group displayed a reduction in body fat mass, results also showed a reduction in testosterone levels. In addition, there was a decrease in insulin-like growth factor, another hormone that plays an important role in muscle growth and development (5) . Four other trials observed decreased testosterone levels in 8-hour time-restricted fasting interventions combined with regular resistance training (7) . While more research is required, recent research has highlighted the potential negative link between fasting and testosterone levels.

Does fasting burn fat?

While fasting can support weight loss, effectively burning and losing fat requires a comprehensive approach. Achieving sustainable fat loss requires maintaining a calorie deficit, getting adequate nutrition, and staying well-hydrated. Ensuring you get enough sleep and manage your stress levels are also influencing factors. Finally, regular exercise can help accelerate progress by boosting your metabolism.

How many minutes should I work out while fasting?

How many minutes you work out while fasting will ultimately depend on the type of fast you’re doing and the intensity of the session. For example, a 16/8 intermittent fasting workout could still provide ample energy throughout the day, allowing high-intensity and longer-duration workouts to be performed safely. Other methods, such as the 17/7 fast, could also enable ample food intake and support moderate and high-intensity efforts. The general guidelines recommend that adults should aim for at least 150 minutes of moderate-intensity exercise or 75 minutes of high-intensity activity each week. These activity targets can be distributed throughout the week for convenience. Considering this, engaging in a 30-60-minute fasting workout, such as a morning walk or a light jog, is entirely manageable. However, exercising after consuming a suitable meal for moderate to high-intensity workouts is advisable. Doing this supports adequate energy for the work required, supporting optimal performance and recovery (8) .

Blog Editorial team Giulia Ralph, CPT, S&C, SPC

Giulia Ralph, CPT, S&C, SPC

Certified Personal Trainer, Strength and Conditioning Coach

Giulia Ralph is a qualified Nutritionist, Strength & Conditioning Coach, Weightlifting Coach, and Personal Trainer who holds a Bachelor of Health Science in Nutrition and a Post-Graduate Certificate in Human Nutrition.

With over 7 years of experience in nutrition and more than 5 years as a strength coach and personal trainer, Giulia is dedicated to empowering individuals to improve their physical and mental health. Giulia’s passion lies in creating healthy and sustainable habits tailored to each individual’s lifestyle and goals, ensuring an enjoyable and rewarding process. She emphasizes a well-rounded approach to fitness, incorporating strength training, weightlifting, and recently, running, into her routine. Beyond her professional pursuits, Giulia enjoys outdoor activities like snowboarding, hiking, trail running, and mountain biking.

Experience

Over 7 years of experience working with individuals and groups in nutrition
More than 5 years as a strength coach and personal trainer in various gym settings
Served as a Head Coach, leading program development
Featured speaker at the Virtual International Conference (IUGA 2020), presenting key nutrition areas for optimal health and practical applications
Actively involved in community nutrition initiatives dedicated to helping underprivileged populations increase their nutritional knowledge and skills

Education

Deakin University – Graduate Certificate of Human Nutrition
Australian Strength and Conditioning Association – Strength and Conditioning Coach Accreditation
Australian Weightlifting Federation – Club Weightlifting / Sports Power Coach 1 License
Personal Training Academy – Certificate III & IV in Fitness
Swinburne University – Bachelor of Health Science (Nutrition Major)