When and how often to eat for weight management is a very popular topic; over the past decade we have heard:
- “Breakfast is the most important meal of the day so don’t skip it.”
- “Eat five-six smaller meals every few hours to keep your metabolism working”.
- “Eat three meals a day; breakfast, lunch, and dinner with no snacking”.
Intermittent fasting has gained a lot of attention because it goes against everything we have always practised or been advised to do.
What is Intermittent fasting?
Intermittent fasting is a recent theory surrounding the concept that involves employing short-term fasting periods (usually by skipping breakfast) in an attempt to improve body composition and general health.
Methods of Intermittent Fasting:
There are three defined types or methods of intermittent fasting:
1. Alternate day fasting:
The most studied method of intermittent fasting, involving fasting for a whole day (24hours) and feeding the next day with no specific caloric restrictions.
2. Whole-day fasting
This method involves fasting for 1-2 whole days in a week and feeding the remaining days with no specific caloric restrictions.
3. Time-restricted feeding
This method involves feeding for only 4-8 hours a day and fasting for the remainder of the day. For example, eating between 12pm-8pm only, leaving a 16-hour gap of fasting.
How does Intermittent Fasting work?Once you pass the 12-hour mark from dinner the night before you are officially in a fasted state and your body begins to rely on stored fat for energy.
What is the difference between fed and fasted state in the body?
- During the fed state, the body produces insulin which signals the body to store excess glucose in your fat cells. During this process, the burning of fat does not occur.
- During the fasted state, insulin levels are low while glucagon levels are high. This signals the body to start burning stored fat cells for energy.
Currently, many people rarely spend more than 12 hours in the fasted state; as a result, our bodies rarely use fat for energy, while the glucose-burning pathways are overworked. Eventually, insulin is high all the time leading to insulin resistance and causing obesity and other chronic diseases.
This is where intermittent fasting can help!
A study published in 2015 states that intermittent fasting can help reduce body weight, decrease fat mass, and lower total cholesterol, triglycerides, and low-density lipoprotein (LDL) cholesterol. Resulting in a reduced risk of chronic diseases such as obesity and diabetes, as well as improving wellbeing and quality of life.
Tips for making Intermittent Fasting work for you:
- You can drink any non-caloric beverages during fasting – water, coffee, tea.
- Eat mostly whole foods – lean meat, fish, eggs, fruit/vegetables, nuts/seeds, whole-grains, high fat dairy, and avoid highly processed refined carbs.
- Combine with exercise – especially on feeding days, cardio or strength training is great for body composition.
- Start slowly – when beginning intermittent fasting it is normal to feel hunger and have low energy levels as your body adapts to the new energy source. Begin by using the time-restricted method and just push breakfast by an hour or two at first.
- Be kind to yourself- stay flexible and fast for as long as convenient (anything beyond 12 hours is going to be beneficial).
- Don’t worry about losing muscle – if you eat plenty of protein on eating days and exercise regularly you are very unlikely to lose muscle from intermittent fasting.
- Consult your doctor before initiating intermittent fasting, especially if you are diabetic.
1. Tinsley G, La Bounty M, 2015, Effects of intermittent fasting on body composition and clinical health markers in humans, Nutrition Reviews, Vol. 73(10): 661-674
2. Dr. Naiman T, 2018, Time-restricted eating-a detailed intermittent fasting guide, Diet Doctor.