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Intermitted Fasting 101

Updated: May 7

The subject of intermitted fasting comes up frequently when maneuvering through all the different dieting types. What are the benefits of intermitted fasting? Will it help me drop body fat? Is there different types of intermittent fasting?

My clients usually asking these questions when they are working on finding the right balance for themselves and developing there ground work with nutrition. Sometimes we like to try to find something that will jump start our motivation, or help us have a better understanding with "food timing ".

The best thing you can do for yourself before trying any types of fasting techniques is make sure you have a solid understanding of basic nutrition. The problem with jumping into a fast , is if you do not get adequate protein, carbohydrates, and healthy fats (macronutrients) with each meal and proper portion sizes under our belt , then we have gaps in your nutrition.

Lets review some of the basic fundamentals of nutrition:

  1. Consume your macronutrients with each meal ( protein, carbohydrates, and fats)

  2. Consume each macronutrients at the appropriate portion sizes for each meal consumed; protein is a palm size and thickness, carbohydrate is a cupped handful, and fat is a thumb size down to the second knuckle.

  3. Have your hunger cues in check; do you take time eating your food? Do you eat without any distractions ? If we eat to fast and are distracted, we consume up to 300 more calories per meal on average . If we do not chew our food properly which can cause less nutrients to be consumed through the saliva , and will take a longer time in the GI tract t o break down and absorb the nutrients we need. This can also cause bloating, digestion issues, and throws your hormones out of control, especially our insulin.

  4. Do you eat until your only 80% full, but not filling up entirely at every meal? If you eat until your full then your satiety hormone are not working the way we want them too. Getting a good "hold" on how we are consuming food, the rate of consumption, and do we stuff our self every time will change your eating habits and how your brain signals when you are full.

  5. Do you get adequate amounts of sleep every day? 7 to 8 hours at most? If we do not get enough sleep, we are known to consume more sugar because our insulin rises, it raises our heart rate, body temperature, we do not repair tissue adequately, we will be missing out on key functions of the brain, your immune system will be less effected to where you will become sick, increases your rick of heart disease and other inflammation-related illnesses. Poor sleep is a direct correlation to increase body fat; this disrupts appetite regulation, causes you to feel hungrier, lead to increased calorie intake. Lack of sleep also reduces performance during exercises; slow reaction time, low energy and endurance capacity, depressed mood, and your energy is spread thin so exercises will be less encouraging. ( if you noticed sleep is pretty important).

  6. Do you have emotions linked to food? If you have a hang up on food already then try to throw a complex food schedule, this can create eating disorders overtime if you are already have a bad relationship with food. The best thing to do here is start out by talking to a licensed professional like a dietitian or psychiatrist to talk about food additions and eating disorders, and what step that you need to take to improve your relationship with your food.

If you have answered any of these questions with a " I need to improve on this area," then take a step back from food timing techniques and please work on your foundation. You can't build from a crumbling foundation, if you do then it will probably not stand very long before you have to start back from the beginning .

Now that we went over the nutrition fundamentals lets talk about fasting.

What is intermittent fasting ? Intermittent fasting is where you split your 24 hours day into two time of eating and fasting, spread out for a number of days or weeks "frequency", length of the fast, and how involved the fast is. We already "fast" every day if you were not aware of this. We fast when we sleep and this helps our body repair, digest, and absorb energy and nutrients we need for the coming day.

There are so many combinations of fasting types , but I would like to put few below that PN nutrition Dr. John Berardi has done case studies and tried personally:

1. Alternate day fasting (ADF)

36-hour fast/12-hour feed

With this plan you simply eat every other day. So on Monday, you’d eat within

a 12-hour window, say, 8 AM to 8 PM. Then you’d fast overnight on Monday,

and all day/overnight on Tuesday. You’d eat again from 8 AM to 8 PM on

Wednesday. And so on. Alternate day fasters are encouraged to make good

eating choices, but they’re allowed to eat what they want on the non-fasting


2. Meal-skipping


Some IF proponents believe we should behave like our evolutionary

ancestors did. As humans evolved to get their food and exercise randomly,

so should we. This brand of IF includes eating unprocessed “evolutionary

friendly” food (think Paleo-diet type), randomly cycling daily calorie intake,

and randomly skipping a breakfast or dinner meal once or twice a week. The

rules are very flexible.

3. Eat Stop Eat

24-hour fast, 1 or 2 times per week

On this plan, you fast for a full 24 hours once or twice per week, eating

sensibly (higher protein, minimizing processed foods, etc.) the rest of the

week. It’s flexible: You can choose whichever 24 hours you want. Want to

fast from breakfast to breakfast? That’s cool. Just eat breakfast on Monday,

and don’t eat again until breakfast on Tuesday. Want to fast dinner to dinner?

That’s cool too. Eat dinner on Wednesday, and don’t eat again until dinner on


4. Leangains

16-hour fast/8-hour feed

This brand of fasting is based on an 8-hour feeding period followed by a

16-hour fast. However, it also layers a few other food rules on top. The diet should be high in protein, should cycle carbohydrates, should include fasted training, and should use nutrient timing (eating the bulk of your calories during the post-exercise period). On this plan, you fast from, say, 9 PM on

Monday night until 1 PM on Tuesday afternoon. If you’re going to exercise,

you’d do so just before 1 PM on Tuesday, with 10 g BCAAs (branched chain

amino acids) during training. After training, you eat 2-3 meals before 9 PM,

with your biggest meal coming right after exercise. The fast begins again on

Tuesday evening until Wednesday at 1 PM, and repeats every day.

5. Warrior Diet

20-hour fast/4-hour feed

On this plan, you would either fast, or eat very small amounts of specifically

recommended foods, for the first 20 hours of each day, working out during

this period of under eating. Then, you would eat the majority of your daily

intake within a 4-hour over feeding window. After that 4-hour over feeding

period, you would repeat the under eating/fasting for the next 20 hours.

Generally, most people place their 4-hour over feeding window at the end

of the day, as it’s more convenient for family dinners and after-work training

sessions. However, modifications can be made based on individual and

scheduling differences.

Now that we have some ideas on how to perform some of the fasting techniques lets find out what the health benefits are.

Fasting has a handful of health benefits that you can reap the benefits from even just doing a 24 hour fast once a week! Restricting calories or fasting for longer periods of times can prolong health of nervous system via perturbations to fundamental metabolic and cellular signaling pathways that regulate aging. Calorie restriction and fasting affects energy and oxygen radical metabolism, and cellular stress response systems that protect neurons against environmental and genetic factors that effect us during aging. This can also combat Alzheimer's and Parkinson's disease. (Martin, B., et al. 2006)


  • cellular turnover and repair (called autophagocytosed)

  • fat burning (increase in fatty acid oxidation later in the fast)

  • growth hormone release later in the fast (hormonally mediated)

  • metabolic rate later in the fast (stimulated by epinephrine and

norepinephrine release).

  • Improved appetite control (perhaps through changes in PPY and ghrelin)

  • blood sugar control (by lowering blood glucose and increasing insulin


  • cardiovascular function (by offering protection against ischemic injury to

the heart)

  • effectiveness of chemotherapy (by allowing for higher doses more


  • neurogenesis and neuronal plasticity (by offering protection against


Some of these benefits have been shown to work more based on the length of the fast usually for 20-24 hour time period if sedentary. But if your work out more often than not then the recommended amount would be 16 - 20 hours with out food. That being said research has suggested that it is recommended to be doing some type of exercise routine during fasting to increase the benefits.

Remember to always have the your fundamentals down before trying a new diet technique. Also always talk with a health provider before starting a new diet technique as well to make sure there are no adverse effects to medication and to talk with your doctor for more recommendations and suggestions.


Berardi J. ,PhD. Scott-Dixon K., PhD. Green N. "Experiments with Intermittent Fasting". 2018 Precision Nutrition.

Martin, B., Mattson, M. P., & Maudsley, S. (2006). Caloric restriction and intermittent fasting: two potential diets for successful brain aging. Ageing Research Reviews, 5(3), 332-353.

okolov, A. N., Pavlova, M. A., Klosterhalfen, S., & Enck, P. (2013). Chocolate and the brain: neurobiological impact of cocoa flavanols on cognition and behavior. Neuroscience & Biobehavioral Reviews, 37(10), 2445-2453.

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