You’ve probably heard of intermittent fasting in some way, shape, or form and you’ve likely formed some sort of opinion about it based on your experience or the information you’ve been presented. If it’s something you’ve been considering to help your weight loss plan or you simply want more information, here is a beginner’s guide to intermittent fasting.
Intermittent Fasting (IF) really couldn’t be simpler: you go for a period of time when you are eating, and then a period of time when you are not eating. In fact, you already do this because you eat during the day and then don’t eat while you are sleeping. IF has a lot of hype around it, for great reasons which we will get into, but really it is the more basic and obvious thing in the world. Eat. Then don’t eat for a while. And that’s your day.
You may be asking yourself if IF is safe, since you’ve been told all your life that six small meals a day is ideal and that breakfast is the most important meal of the day. I’m here to tell you that I don’t care if your physician told you this or your next door neighbor: it’s a bunch of hooey.
Becoming acclimated to IF can improve your blood sugar levels, keep your energy stable throughout the day, erase your hunger, and give you great weight loss results.
When you intake food, it is broken down into macronutrients which go zipping around to different parts of your body to provide energy. Energy that isn’t used immediately, gets stored in the liver, the muscles, the blood stream, or, lastly, as body fat. When you are not taking in new calories and your body needs to use energy, it will go to these stored sources.
If it has been many hours since you’ve eaten (a fasted state), these energy stores will get used up: first your blood sugar, then your liver and muscle stores, then finally when nothing else is available, your stored body fat. This is what you want to achieve if your goal is to lose “weight.”
About 4-6 hours after you’ve eaten your last meal is when your body has processed all of this fuel and you enter a fasted state. At this point, you can actually get into a ketogenic state where you body begins producing ketones and using fat for energy in the absence of glucose (from your blood, liver and muscles). Ever heard of the keto diet? Well, in essence, IF is like a mini ketogenic state every single day which is one reason it’s so effective for weight loss.
As with most things in life, it’s a good idea to start moderately and allow your body time to adapt to the process of IF. Take a look at what your current eating window looks like and go from there. If you normally eat between 6am and 9pm (15 hours) start off for a week or so by shortening that to 9am to 9pm (12 hours).
If you can work that into your schedule and it feels good, try skipping breakfast altogether, don’t eat until noon and finish eating by 8pm. This would give you the common IF schematic of 16:8, meaning you are fasting for 16 hours, eating for 8. This is a great place to start for beginners. You will still be eating two whole meals a day and a snack in between if you need it and most people find it’s not really that difficult to skip breakfast.
This is a solid daily fast and most people never feel the need to go beyond this. In my experience, I have found that this level of fasting sits really well with me and with many of my female athletes and clients. Sometimes less is more. But if you are looking to ramp up the intensity of your fast and your weight loss results, you could try shortening your eating window even more.
Eating “OMAD” or one meal a day is a more intense and extreme version of IF. One meal a day is more realistically about a 2 to 4 hour eating window, since it’s tough to eat everything you need for the day in one sitting (your poor stomach!). Many people swear by this strategy for its A) convenience with their busy schedules and B) the sheer simplicity of only eating once.
Again, start moderately and pick what feels right for you and your life. You may not jive with OMAD, but be fine with a 6 hour eating window. There really isn’t any reason to complicate this process. Keep it simple and intuitive and fit it into your life.
If your primary goal with Intermittent Fasting is for weight loss, then my biggest caution would be not to go bananas during your eating window. Although this is a unique eating strategy, you still need to practice the basics of holistic nutrition and intuitive eating like not eating past 80-100% fullness, prioritizing protein and nutrient-dense foods, and minimizing processed snacks.
If your body is adjusting well to IF, you shouldn’t feel too hungry during your fasting window (more on that in a minute) and by the time you are ready to eat your first meal of the day, you won’t feel the need to gorge. The second most common mistake I see with Intermittent Fasting (read on for the most common) is when people think they need to stuff themselves to make up for what they didn’t eat during their fast. Again, if your goal is weight loss, this is a big-time no-no. Not only will it be giving you more calories than you need, but it will also give you pretty terrible gastrointestinal distress.
This is also not a green light to eat whatever you want. Yes, you can be eating the foods you love, but you still need to be stopping when you’re full and getting your daily nutrition requirements (Read “Why Macros Matter” for info on protein requirements based on your body).
A great idea for your first meal of the day, whatever time that is, would be to eat a low-glycemic meal high in protein and saturated fats. What do I mean by low-glycemic? More or less, this means low in carbohydrates. When you eat a lot of carbs, your blood sugar will spike hard, especially after fasting all day and the previous night. This will cause a big surge in energy (sugar rush) and then a crash a few hours later. If you can eat a meal that does not spike your blood sugar, it will keep you in a mild state of ketosis, allow you to continue burning fat, and keep your hunger satiated for many more hours until you eat again.
My favorite way to break a fast is 3 whole eggs with avocado and coconut oil, or a salad with seeds, cheese and fatty fish. Yum. Leave me a comment if you have any great ideas for a break-fast meal or questions about what that would look like.
This is the most common issue I see that will derail the effectiveness of a fast. Somewhere along the line, many people became convinced that if it’s liquid, it won’t take you out of a fasted state. People will believe they are Intermittent Fasting when really, they are drinking lattes with milk, bone broth, diet soda, or loads of coffee with cream and sweetener.
The first rule of success for IF is to consume no calories during your fasted period. Technically, a pure fat source like coconut oil or heavy whipping cream will not break a fast, but if the goal is to lose weight with Intermittent Fasting, then skip it altogether. These foods will keep you in a fat-burning, ketogenic state, however, you are giving your body an external source of energy, and remember that in order to lose fat, you want to be burning your own stored fat.
I’m sure you’re wondering about sugar-free, calorie-free sweeteners and things like diet soda. That’s calorie-free, so it should be fine, right? Well, actually, artificial sweeteners have been shown to produce an insulin response in the body which will shut down the fast and those protective mechanisms that are keeping you from feeling hunger.
What’s the best thing you can put in your mouth during your fasted window? You guessed it: water. In fact, hydration will become even more important while you’re fasting. And since you aren’t taking in any electrolytes from food during this period, you’ll need to be getting it from elsewhere. Adding a pinch of sea salt or imalayan salt to your glass of water is a great way to make sure you are hydrating, and maintaining an electrolyte balance (Read “The Importance of Electrolytes” for a breakdown on how this works).
The answer to this can depend on what type of exercise you do. However, I would suggest that fasted exercise is ideal, particularly when your eating window is shorter and I will explain why. Once you have eaten, your body will ideally be in the “rest and digest” parasympathetic state. Exercise gets you into more of a sympathetic nervous system state which is not great if you have a lot of food in your stomach because your body will shut down digestion.
If you are doing aerobic training and some resistance training, then you can exercise anytime during your fasted window. You can play around with different workout times and see when your energy is best, but keep in mind that the body can get used to quite a lot if given time.
If your training is more intense with lifting a lot of heavy weights over long training sessions (more than 45 minutes) then my advice would be to train right before you break your fast. This will allow you to refuel as soon as you are done training, giving your body building blocks to repair and recover from a hard training session. You could also consider drinking a protein shake during your workout to keep from breaking down muscle tissue, although IF has natural, muscle-sparing benefits.
While Intermittent Fasting, your body produces more human growth hormone, which prevents muscle catabolism (or the breaking down) of muscle tissue. This is one of the major positives of using Intermittent Fasting for weight loss as opposed to eating all throughout the day deep in a caloric deficit, which can lead to a lot of muscle catabolism. So, IF allows you to break down fat without breaking down muscle tissue.
Other than growth hormone, Intermittent Fasting affects your other hormones like insulin. IF and being in ketosis throughout the day improves insulin sensitivity. Having good insulin sensitivity allows your body to more effectively break down food for energy. Insulin insensitivity, or resistance, is what can lead to Diabetes II.
Being in a fasted state also releases BDNF (brain-derived neurotrophic factor) which increases the production of new brain cells, leading to improved mental clarity. There have also been a number of studies to show that fasting can reduce the growth of tumor and cancer cells and reduce the risk of heart disease and neurodegenerative diseases like Alzheimer’s.
One aspect that contributes to the massive array of health benefits from Intermittent Fasting is a mechanism called autophagy. Autophagy is a process of cellular repair and detoxification that is always happening in the body, but fasting gives it a huge increase. Autophagy catabolizes (breaks down) the components of our cells that are damaged or junky and clears out oxidative damage from the body. (More on Autophagy)
Hopefully I have sold you on just a few of the benefits of Intermittent Fasting for weight loss and for your overall health. If you’d like to try integrating it into your life, here are my top three tips for making it successful.
Be sure to reach out or leave a comment if you are new to Intermittent Fasting and have questions about the process.