Intermittent Fasting: Is it good for you? If so, what’s the healthiest way to go about it?

You may have heard about intermittent fasting or IF. Is it just another health fad? Is it good for you? How do you go about it? I will discuss a few IF options and the benefits as well as possible precautions to take in certain health conditions.

Intermittent fasting allowed our Paleolithic hunter gatherer ancestors to survive when there was a shortage of food. (1) Intermittent fasting is thought to preserve fat-free mass, maximize fat loss while maintaining physical function and reduce declines in resting energy expenditure to help prevent weight gain and aid in weight loss. (1) Adequate protein intake is necessary in maintaining fat-free mass with weight loss. The recommendation is to consume about 0.9 gm of protein per kg of body weight. (1) Another important aspect of retaining fat-free mass is exercise and some studies have shown IF can enhance physical performance. (1)

You most likely already do some form of IF without even trying. If you eat dinner at 6 or 7pm and don’t snack before bed and don’t eat breakfast until 7 or 8am the next day, you are intermittently fasting. You are allowing your body a chance to rest and digest during those 10-12 hours.

When we rely on snacks or small meals every few hours, this signals the body that there is a constant supply of energy coming in, therefore there is no reason to burn stored fat. (2) Burning fat during intermittent fasting can aid in neutralizing the acidity in the body making it more alkaline, detoxify fat-soluble toxins stored in our fat cells, and helps us to maintain a healthy weight. (2)

Various benefits associated with IF include reduced levels of insulin, the hormone responsible for the uptake of glucose into our cells and leptin, the hormone that is responsible for satiety. IF improves insulin and leptin sensitivity, improving the uptake of glucose into the cells for energy and keeping our hunger in check by improving leptin sensitivity and preventing leptin resistance. (1) Several other benefits to IF include reduced body fat, reduced resting heart rate and blood pressure, and increased heart rate variability. (1) Intermittent fasting is also associated with reduced inflammation which can offset other health conditions such as diabetes, cardiovascular disease, and even Alzheimer’s disease. (1)

There are several different ways to fast intermittently. These are the healthiest options in my opinion.

The first being the 16/8 Method where you fast for approximately 16 hours each day. The 16/8 Method involves fasting every day for 14-16 hours and restricting your daily “eating window” to 8-10 hours. This method is also known as the Leangains protocol and was popularized by fitness expert Martin Berkhan. Within the eating window, you can usually fit in 2 to 3 meals.

This method of fasting can be as simple as not eating anything after dinner and skipping breakfast. For example, if you finish your last meal between 6 to 8 pm and then don’t eat until 10 am to 12 noon the next day, then you are technically fasting for 16 hours.

It is generally recommended that women only fast 14-15 hours, because they seem to do better with slightly shorter fasts.

For people who get hungry in the morning and like to eat breakfast, this can be hard to get used to at first. However, many breakfast skippers instinctively eat this way anyways. You can drink water, coffee or another non-caloric beverage during the fast, and this can help reduce hunger levels.

It is very important to eat mostly healthy foods during your eating window. This won’t work if you eat a lot of junk food or excessive amounts of calories. I eat this way myself and find it to be 100% effortless.

Bottom Line: The 16/8 method involves daily fasts of 16 hours for men, and 14-15 hours for women. On each day, you restrict you’re eating to an 8-10 hour “eating window” where you can fit in 2-3 meals.

Another IF option is Spontaneous Meal Skipping: Skip meals when convenient. You don’t need to follow a structured intermittent fasting plan to reap some of the benefits. Simply skip meals from time to time, when you don’t feel hungry or are too busy to cook and eat. It is a myth that people need to eat every few hours or they will hit “starvation mode” or lose muscle. The human body is well equipped to handle long periods of famine, let alone missing one or two meals from time to time. Our ancestors did this and stayed lean at a healthy weight!

So, if you’re not hungry one day, skip breakfast and just eat a healthy lunch and dinner. Or if you’re travelling somewhere and can’t find anything you want to eat, do a short fast. Skipping 1 or 2 meals when you feel so inclined is basically a spontaneous intermittent fast. Just make sure to eat healthy foods at the other meals.

Bottom Line: Another more “natural” way to do intermittent fasting is to simply skip 1 or 2 meals when you don’t feel hungry or don’t have time to eat.

Intermittent fasting isn’t for everyone, if you have diabetes, I recommend checking with your health care provider before doing any sort of fasting. If you have an eating disorder such as anorexia or a diagnosis of adrenal insufficiency/fatigue I don’t recommend intermittent fasting. If you have symptoms of hypoglycemia or low blood sugar such as fatigue, dizziness, shakiness, sweating, extreme hunger, irritability or moodiness, anxiety or nervousness, and/or headaches in between meals I recommend checking with your health care provider and work towards balancing your blood sugar levels before undertaking intermittent fasting. (3) To ease hypoglycemia, I recommend eating enough protein at each meal, along with healthy fats, this will help stabilize your blood glucose levels between meals. Avoiding or limiting consumption of refined sugar and processed foods can keep your blood sugar in check as well.

*IF in Women

Intermittent fasting (IF) is not the same for women as it is for men. Unfortunately, intermittent fasting was studied almost exclusively in men which showed tremendous benefit. Where the female physiology was not considered in most of the research literature.

Women are already more proficient in burning fat for fuel compared to men.

Women’s muscle mitochondria already use, and uptake free fatty acid and estrogen increases free fatty acid use which spares carbohydrates.

Women get the same great benefits of fasting from exercise. If you want to fast, just don’t eat after dinner, and eat something (carb, protein, healthy fat) 30 minutes prior to exercise in the morning. That comes out to a 10-12 hour fast overnight.  If you want to give IF a go, I recommend doing just 15 hours vs 16 hours of fasting.

Fasted Training

Fasted training puts an incredible amount of stress on the body leading to endocrine and thyroid dysfunction, inflammation, and even anemia. We women need carbohydrates for proper endocrine function. So, eat those carbs ladies!

Low Carbohydrate Diets in Women

When women drop too low in carbohydrates, it causes a drop in estradiol with a rise in estrone (which is the type of estrogen that is released from fat tissue) which signals our body to store more fat along with cortisol (progesterone is converted to cortisol, which also signals fat storage under prolonged periods of stress).

The difference between men and women in this state that simulates famine. Women become more “masculinized” in our reproductive status and conserve fat (with high fat/low carbohydrate diet). From a survival standpoint, your body is thinking famine, and in a widespread famine, the last thing that is needed is reproductive capabilities. But in men, the low carbohydrate famine mechanism is to become ready to fight, so they lean up, increase anabolic activities, and increase testosterone.

This alteration in reproductive hormones is why so many women struggle with IF and keto diets, while men tend to thrive on them.

References

1. Mattson
   MP, Longo VD, Harvie M. Impact of intermittent fasting on health and disease
   processes. Ageing Research Reviews.
   2017; 39: 46-58. http://vb2et3bd6j.search.serialssolutions.com/?V=1.0&sid=PubMed:LinkOut&pmid=27810402
2. Douillard
   J. Colorado Cleanse. 4^th
   Ed. Boulder, CO: Life Spa; 2016.
3. https://www.mayoclinic.org/diseases-conditions/hypoglycemia/symptoms-causes/syc-20373685
4. Sims, Stacy. Roar. New York, NY: Rodale; 2016.