What is Intermittent Fasting?
Intermittent Fasting is an eating pattern consisting of a eating and a fasting phase. The focus is on when you eat. IF is meant to reflect the eating patterns of our hunter-gatherer ancestors. This is a strategy to help strengthen the body’s ability to exist in a fasted state. The body will burn fat instead of continually burning sugar from the fed state. Time in the metabolic state is a form of a metabolic workout which results in weight loss.
Variations to Intermittent Fasting
- 16/8: Fast for 16 hours each day, eat during 8-hour window (2-3 meals). This is the most popular way to IF. It does not matter what time of day you are eating or fasting, but you should be in a fasted state for 16 hours total before eating again. You may consume non caloric drinks including water, tea and black coffee during the fasting period to help control appetite. The goal is to keep your blood sugar steady by refraining from grazing throughout the eating window.
- 5:2: Eat normal for 5 days of the week and for any 2 days of the week eat 500 calories only.
- Eat-Stop-Eat: Do a full 24 hour fast 1-2 x weekly. Do not eat from breakfast to breakfast, lunch to lunch, or dinner to dinner. You are not consuming calories for a 24-hour period. You should consume at least half your body weight in oz of water daily. You may also consume non caloric drinks during the fasted period including water, black coffee, or tea.
How to Eat
Although the focus in not on what you eat but when you eat, it is still advised to consume healthy choices to obtain optimal results. This includes limiting processed foods and increasing intake of whole foods.
- Fruits: apples, bananas, berries, oranges, peaches, pears, etc.
- Veggies: broccoli, cauliflower, cucumbers, leafy greens, tomatoes, sweet potatoes, etc.
- Whole grains: quinoa, brown rice, oats, barley, buckwheat
- Healthy fats: olive oil, avocados, and coconut oil
- Sources of protein: meat, poultry, fish, legumes, eggs, nuts, seeds
- Alcohol is okay to consume in moderation; however, it does count as caloric intake so should only be consumed during eating times as it affects blood sugar. Avoiding drinks high in carbohydrates and sugars (beer and mixers including soda pop) should be avoided.
- Desserts and snacks should be limited. If consumed it is advised to eat during one of the set meal times to allow blood sugar to stabilize after caloric intake.
Exercise
A typical exercise prescription can be written using the FITT mnemonic.
- F – Frequency: Number of days per week (ideally five or more)
- I – Intensity: Moderate or greater (moderate = too winded to sing but can talk with exercise) – brisk walk, run, stairs, bicycle, elliptical, swim at 60-80% maximum heart rate. Use a pedometer that tracks your steps and heart rate. To calculate your maximum heart rate by subtracting 220 – your age (40 y/o ex: 220 – 40= 180, your workout heart rate should be between 108 to 144).
- T – Time: Number of minutes per session (at least 30 minutes a day, 5-7 days a week)
- T – Type: Activities that involve major muscle groups.