Intermittent Fasting (IF)
Adapted from Dr Arien van der Merwe’s book: Managing Diabetes and Related Health Challenges
Written by Dr Arien van der Merwe
Based on conclusive research published over the past 2 years, IF is one of the best ways to lose weight (especially fat weight) and reverse diabetes (while reducing your risk of heart disease). It makes such sense, it is actually not ‘new’ at all, being the way our ancestors lived, that it is quite strange that it has only been ‘proven’ by science so very recently! Many studies have also demonstrated the longevity potential of living this way.
What is Intermittent fasting?
There are various ways of intermittent fasting, but the most practical is to restrict eating to an 8 hour period every day, with a 16 hour period of fasting (16:8), which fortunately includes the hours you’re sleeping!
- It takes about six to eight hours for your body to burn the carbohydrates stored in your body (liver and muscles) as glycogen.
- After that the body begins to burn fat as its primary fuel, hence the 16 hours of fasting to support the body’s fat burning mode.
- It takes about 6 weeks to make this transition. During this period, you might experience sugar cravings (I didn’t).
- You can use coconut oil to supply fuel to curb cravings and provide an interim source of energy until your body starts to effectively burn your own fat.
- If you experience hypoglycemic (low blood sugar) symptoms such as headaches, weakness, nausea, tremors or irritability, take a break from exercising and break your fast with the meal you would have had later.
When following the IF protocol, you are not supposed to starve yourself, or even to restrict the amount of food you eat. The prescription is simply to make healthy food choices, limiting or avoiding food containing mainly carbohydrates (white bread, pasta, refined flour based, and so on), replacing them with low GI/GL nutrient dense carbohydrates, vegetables, fruit, nuts, lean protein, healthy fats and plant oils as found in coconut oil, olive oil, olives, butter, eggs, avocados and nuts.
It might take several weeks for your body to shift into fat burning mode, but once this happens, your body will preferentially burn stored fat and not rely on carbohydrate intake for fuel.
Some of the health benefits of IF:
- Prevents and stops inflammation
- Improves circulating blood glucose levels
- Helps prevent type 2 diabetes
- Delays progression in existing type 2 diabetes
- Reverses type 2 diabetes
- Improves insulin levels and insulin sensitivity
- Improves pancreatic function
- Protects against cardiovascular disease
- Modulates levels of dangerous visceral fat
- Reduces LDL and total cholesterol levels
- Improves unhealthy lipid (triglyceride) levels
- Reduces blood pressure
- Improves metabolic efficiency and body composition
- Causes significant reductions in body weight in obese individuals
- Reproduces some of the cardiovascular benefits associated with physical exercise
Intermittent fasting and exercise:
- Combine IF with exercise (high intensity interval training or HIIT, see ‘Exercise as Medicine’, pg. 160 for more info) of 10-20 minutes before you break your fast. Do this for at least 3 months. The results are worthwhile! Read more about it in the chapter on my own healing journey (Chapter 10).
Exercise enhanced IF was evaluated in a clinical trial with volunteers who had an average weight of 90.5 kg, BMI of 32.2 (>30 is considered obese), waist circumference of 106 cm and fasting insulin indicating insulin resistance. After 3 months, participants lost an average of 4 kg and even more importantly, about 7 kg of fat and 7.5 cm around the waist! Insulin levels dropped by 25%, returning to normal.
Intermittent fasting and diet:
The effects of three different diets in 19 participants who had type 2 diabetes, were examined. All participants consumed breakfast and lunch under supervision in a diabetes ward. The caloric intake in the three diets examined was the same, but the diets differed in the following ways:
- A conventional low fat diet with 45-56% carbohydrates
- A Mediterranean diet with coffee only for breakfast (similar to 16:8 intermittent fasting) and a big lunch with 32-35% carbohydrates
- A moderate low carbohydrate diet with 16-24% carbohydrates
All participants tried all three diets, one diet each day in randomised order. The Mediterranean diet was higher in fat. The participants skipped breakfast and had a big lunch instead (an equal number of calories at breakfast and lunch to other participants). This led to excellent blood sugar levels in the morning. After the big lunch, blood sugar levels were even similar to those who had the small, low fat lunch!
- The Mediterranean Diet:
It is interesting to note that in several Mediterranean countries (Italy, Portugal, France and Greece), it is a habit to skip breakfast. Many people prefer not eating breakfast early in the morning, but our cultural and common dietary advice and erroneous beliefs, insist on having breakfast early in the morning. Therefore, once again, listen to your body – IF is often our bodies’ preferred way of living.
Skipping or delaying breakfast, as expected, did not elevate insulin levels, while the big lunch produced a substantial peak.
- The Low Fat Diet:
The low fat diet contained mostly carbohydrates and, as expected, caused the highest average elevations of insulin and blood sugar levels throughout the day. This is bad news for diabetics, both with a decreased insulin sensitivity and with difficulty producing enough insulin to manage their blood sugar levels. The low fat, high carb diet most diabetics are recommended to follow, tested the worst!
- The Moderate-Low Carbohydrate Diet:
The low carbohydrate diet clearly produced the lowest average insulin levels throughout the day, despite what certain skeptics claim. This has been a finding repeated in many previous studies. A low carbohydrate diet produces much lower levels of the fat storing hormone insulin. This represents an advantage to all of us who want to burn more fat, store less body fat and manage our insulin and blood sugar levels.
This exciting study once again illustrated that a moderate, low carbohydrate diet (containing more healthy fats and plant oils) produces the best results. Skipping or delaying breakfast and eating a bigger lunch or brunch (IF), as is common in several Mediterranean countries, is beneficial. The Mediterranean Lifestyle has long been touted as the best way to live – this is probably one of the reasons!
The two advantages found in the study can be combined. Following a medium to high fat, low carbohydrate diet and skipping, or delaying breakfast, would create the best positive effects.
Dr Arien’s recommendations:
‘My recommendation is intermittent fasting (IF) using the 16:8 guideline (16 hours fasting, 8 hours eating a delayed brunch, snack if necessary and early evening meal), combined with medium to high intensity interval training (HIIT) exercises, 20-40 minutes per day, preferably before breaking your fast. This will increase insulin sensitivity on your muscle cell receptors, allowing the glucose to move from your bloodstream into the cells where it can be used as fuel, while simultaneously burning fat for more fuel.
Don’t worry, you will not pass out or feel weak – quite the opposite! Start slowly, even delaying breakfast for 1 hour later than usual, and simply stretching, moving your body gently, gradually increasing the IF and HIIT practice every day, and before you know it, 16 hours of fasting with a daily (or even twice daily) 15-20 minute HIIT exercise session before eating, will become your second nature. It’s great for mind, mood and body; heart, brain and diabetes!’