I am asked many questions about intermittent fasting on a daily basis. Here are the answers to the most frequently asked questions.
Obviously there is not enough room in this post to answer every FAQ about intermittent fasting and flexible dieting. Most people who are serious about intermittent fasting and flexible dieting also take a look at my very comprehensive Fat Loss Fast System. 
1. What is Intermittent Fasting?
Intermittent fasting (IF) is not a diet. You still eat your normal amount of food, you just eat it in a smaller time frame, referred to as your eating window. It is simply a plan telling you when you can eat and when you cannot eat. Since you spend more time fasting than you do eating, it gives your body a chance to tap into its stored fat for fuel.
2. Is fasting just a way for lean people to shed the last 5 pounds of stubborn fat? Will it also work for someone who has 50 to 100 pounds of fat to lose? And how long do you have to be on this fasting diet?
Read my article Who Can Fast for Fat Loss?
3. Will Fasting make me store fat? Will I Enter into Starvation Mode?
If you keep eating meals every two to three hours from the time you wake up until the time you go to bed, you will be chronically suppressing fat oxidation (i.e. fat burning). You will never give your body a chance to burn anything other than the food you are eating. You will have a hard time losing fat.
Fasting decreases your insulin levels. This is good because lipolysis (the process whereby your stored fat is broken down for energy) will finally be able to occur.
Key points:
You burn fat when you are fasting.
You burn food when you are eating.
No, your metabolism will not slow down and you will not enter into starvation mode if you fast. It is ludicrous to equate starvation with skipping breakfast or not eating for 20 hours, or even for two days! According to a 1987 study by Nair et al. in the American Journal of Clinical Nutrition, the earliest evidence of a lowered metabolic rate in response to fasting occurs after 60 hours (with an 8% drop in resting metabolic rate).
A 1994 study published in the British Journal of Nutrition reported no change in metabolic rate among 29 men and women who fasted for three days (72 hours).
A 2004 study published in Obesity Research studied the metabolic effects on women who ate half the amount of their baseline calories over a three-day period. And guess what? There was no change in their metabolic rate.
A 2007 study on 10 lean males showed that undergoing a three-day fast resulted in no changes in metabolism.
A 2005 study published in the American Journal of Clinical Nutrition on the effects of alternate-day fasting on the metabolic rates among males and females showed no change in metabolic rate.
Keep in mind, the longest we will be fasting is 20 hours (not 3 days!), and most of our fast happens during our sleep.
A 2000 study by Zuaner et al. in the American Journal of Clinical Nutrition showed that resting energy expenditure actually increases in early starvation (up to 60 hours) and is accompanied by an increase in plasma norepinephrine. Norepinephrine is a catecholamine in the body that plays a role in the “ fight-or- flight” response, something our ancestors would have relied upon when hunting for food. When the fight-or- fight hormones are released into the bloodstream, they trigger the release of glucose from energy stores and increase fat burning (by releasing fatty acids from your stored fat). This is how your body maintains your blood sugar levels and increases your fuel supply.
This is exactly what my Fat Loss Fast System teaches. You will learn a very simple and effective way to utilize intermittent fasting to melt the fat off your body.
Fasting really works! I started fasting in 2012 and I have been happily living lean and hunger-free ever since. Note that I was born in 1978 and I am an endomorph. 
4. But I thought I had to eat every two to three hours to keep my blood sugar levels stable and to prevent hunger and fainting?
Why is our society convinced that shaking, light-headedness, hypoglycemia, and fainting will occur if they skip a meal, skip breakfast, or exercise fasted? Is it possible that the “perceived symptoms” of hypoglycemia are merely a result of anxiety over not eating? Because it’s a fact that the average healthy person will not experience a drop in blood sugar while fasting. In fact, a 24-hour fast will not place you into a state of hypoglycemia.
Do you think humans could have survived on this planet if our bodies could not regulate blood sugar? As long as you are healthy, then your blood sugar levels are not going to swing wildly from one extreme to another. So no, you will not faint, feel weak, or become confused if you skip a meal or two. Your body will maintain your blood sugar levels even when you can’t stuff your face with food.
Perhaps you worry that you can’t hack intermittent fasting (i.e. skipping breakfast) because you are accustomed to eating from the moment you wake up until you go to bed. Naturally, you assume skipping breakfast would make you hungry.
Let me explain why eating every 2 to 3 hours is the reason why you are hungry: it’s because you have trained your body to be hungry every 2 to 3 hours! The steady stream of carbs with which you are stuffing your face is suppressing your body’s endogenous glucose production. In other words, your body never needs to tap into your stored glycogen or fat for energy because you are constantly stuffing energy (i.e. food) directly into your mouth. Now you’ve trained your body to rely on burning the food you shovel into your mouth for energy. This explains why eating carbs every few hours makes you hungry for more carbs every few hours.
Fasting, on the other hand, has a suppressive effect on hunger. And when you finally do break your fast, you get to eat large portions that promote satiety (appetite satisfaction).
Remember this key point: There is always enough glycogen stored in your liver to meet your immediate energy needs. If you burn through all that stored glycogen, you won’t pass out or get dizzy because your body will start breaking down fat for fuel. Good!
Get started with my Fat Loss Fast System so you can outsmart dieting! Not only will you will learn why fasting works so well for fat loss, but you will also learn how easy it is to implement fasting into your lifestyle.
5. Won't fasting make me hungry?
The answer is no. Most of your fast happens when you are sleeping at night. And contrary to popular belief, the fasting phase has a suppressive effect on hunger. And when you finally do break your fast, you get to eat large portions that promote satiety (appetite satisfaction).
Oftentimes you may think you are hungry, but in actual fact, you are just thirsty. Both hunger and thirst are controlled by the hypothalamus. That explains why you often misinterpret thirst for hunger. So when you feel hungry, drink a glass of water. You can drink as much calorie free liquids as you want during your fasting phase.
6. I'm scared to fast.
7. Can I add a splash of cream or milk to my coffee?
Yes, you can add a splash of cream or milk to your coffee. Fasting works because it keeps your insulin levels low enough to allow fat burning (oxidation) to occur.
8. Will lemon water break my fast?
Read my article called Will Lemon Water Break Your Fast?
9. Is Bulletproof coffee okay to consume fasted?
I do not consume coconut oil or butter in my fasted state. I am not a fan of adding coconut oil or butter to morning coffee, and this is why: Although fats have no effect on insulin, consuming these “extra calories” are not without consequence. If you spike your coffee with butter and coconut oil (a.k.a. “bulletproof coffee”), then you must subtract ~440 calories and ~50g of fat from your calorie allowance. Failure to track these calories will result in weight gain. Furthermore, research suggests “bulletproof coffee” may be boosting hyperlipidemia in otherwise healthy individuals. Consult with your physician.
Please click here for my thoughts on Bulletproof coffee information.
10. Can I have a protein shake during my fast, or will this break my fast? Is there anything I can consume during my fast? Sometimes I get really hungry.
NO NO NO! Eating or drinking calories will raise your insulin levels. Whey protein is notorious for raising insulin levels! Let's explore this further: Dietary carbs will raise insulin more than dietary protein. Dietary fat; however, does not impact on insulin levels. Keep in mind that food is generally a mixture of macronutrients, so you will inevitably raise your insulin levels if you eat or drink calories. Here's the bad news: Insulin stops your body from using fat as a source of fuel (ie. it suppresses fat oxidation). In other words, when your insulin levels are elevated, you are in fat storing mode and you are not able to release fat from your fat stores. Key Point: in order to burn body fat, your insulin levels must be very low. This can be achieved through short-term fasting. So stop eating all the time if you want your insulin levels to drop low enough to allow your body to burn fat.
Remember: Eating prevents you from using your body fat for fuel. Fasting promotes the release of body fat for fuel.
Simmer Down! You can eat again in 16 to 20 hours. It will be awesome and worth the wait. Think of the fast as a major accomplishment. Give yourself a pat on the back for completing it and then enjoy your feast ... a well-deserved reward for a job well done.
Stay busy. If you sit around thinking about food, you will want to eat. Work. Read. Go for a walk. Exercise. Have a nap. Run errands. NEVER SIT AROUND DOING NOTHING when you have a CRAVING. Distraction is key! Stay busy and your hunger won't even be a blip on your radar.
Have some discipline! There. I said it. Conventional dieting with its horrid food restrictions is difficult, but waiting for your next feeding window is not so hard.
Drink lots of calorie-free fluids, water, coffee, tea.
11. Are there any health benefits associated with fasting?
Yes! Click here to read the top 10 health benefits of intermittent fasting. In the meantime, here's a quick list:
- Effortless Fat Loss (Increased lipolysis and fat oxidation)
- Improved Mood (possible from increased concentrations of Brain-Derived Neurotrophic Factor)
- Increased energy and focus (the sympathetic nervous system is dominant, which controls your “fight-or-flight” instincts).
- Increased cellular cleansing (autophagy: prevents and repairs the damage done to our cells by free radicals)
- Decreased chronic systemic inflammation
- Decreased blood glucose levels, decreased insulin levels, insulin resistance improves and insulin sensitivity increases.
- Increased growth hormone levels, increased epinephrine and norepinephrine
- Decreased risk of coronary events
- A 2014 study was released suggesting fasting for 2 days could also help the body fight off disease. This study by the Univeristy of Southern California found that fasting could trigger white blood cell regeneration, which has major implications for people suffering from damaged immune systems (i.e. cancer patients). The study also found that fasting reduces levels of the enzyme PKA, which can increase longevity in simple organisms. They also noted that fasting reduces levels of the hormone IGF-1, which is promising because IGF-1 has been linked to ageing, tumour progression and cancer risk. And lastly, they conducted a pilot clinical trial and found that fasting for a 72-hour period prior to chemotherapy protected patients against toxicity. In other words, short-term fasting protects healthy cells while leaving cancer cells vulnerable to the toxic effects of chemotherapy.
- More free time (Increased productivity)
- Decreased food-related anxiety
- Carbs are permitted, especially at night (carb backloading)
- No more meal prep, you can eat freshly made food
- Satiety when you do eat (Because you eat all your calories in a 4 to 8 hour eating window)
- No more hours doing slow duration cardio
- No need to workout twice a day. Shorter duration daily workouts improve compliance, and therefore, results
- No more chronic daily calorie restriction
- Easy to maintain a robust metabolic rate despite fat loss (thanks to calorie and carb cycling)
- Decreased set point weight (easier to lose weight and keep it off… no more yo-yo dieting)
- From my own experience, intermittent fasting has been the easiest way to lose fat and keep it off since 2012. This is advantageous because the lower and more stable your weight, the lower your chances of having a heart attack, stroke, high blood pressure, high cholesterol, diabetes or cancer.
13. Are there any disadvantages to fasting?
Some people complain of headaches and nausea when they first start fasting. For the majority of people, these symptoms go away after 2 weeks. As always, consult with your physician.
Be warned that fasting can really boost your energy levels and you may have trouble falling asleep, so limit your caffeine consumption to the morning and early afternoon hours only.
Be prepared to go to the bathroom frequently because of your high fluid intake during your fasts.
Be prepared to get very cold towards the end of your fast. Sometimes my fingers and toes become really cold (almost numb). When you fast, there is more blood flood travelling to your body fat, supposedly to help move it to your muscles where it can be burned as a fuel. Because of this increased blood flow to your body fat, your vessels in your fingertips and toes vasoconstrict to compensate. So if you are cold, then rejoice! You are burning fat!
14. Should I eat 1200 calories or less per day for weight loss?
NO! Don't slash your calories. Check out my online Calculator to GUESSTIMATE how many calories you should be consuming... select your TDEE in the results section. I don't recommend daily calorie restriction. In fact, I don't recommend dieting at all! To learn how to "safely diet" and calorie and carb cycle, please check out my Fat Loss Fast System.
A robust metabolism is the secret to fat loss success 365 days a year. The good news is that short-term fasting will not decrease your metabolic rate. Do you want to know what will decrease your metabolic rate? Eating in daily caloric deficit to lose fat! Chronic daily dieting will cause your metabolic rate to slow down, regardless of the style of eating you adopt (i.e. frequent feeding versus intermittent fasting). This is why you should never eat in daily caloric deficit.
15. How do I maintain my results once I reach my goal weight?
Once you reach your weight goal, you will be in maintenance mode. You can cycle your calories and carbs daily, based on your activity and hunger levels. Use my calculator to establish what your daily TDEE (maintenance level calories) will be based on your new weight, height, age, gender and activity level for that day.
16. Is Intermittent Fasting a long-term fat loss solution?
Intermittent Fasting is a long-term solution. You will never have to diet again. In my opinion, it's the easiest way to live lean.
Short-lived diets always fail. In fact, short-lived fat-loss attempts are the reason why you are getting fatter! Unless you can follow the diet for the rest of your life, then the diet will fail you. Remember that intermittent fasting is not a diet. It merely tells you when you can eat and when you can't eat. I have been practicing my Fat Loss Fast System daily since August 2012. Not only did it help me shed my ugly fat, but it has also kept me consistently lean. It requires very little effort on my part, which is why I have maintained and endured my regime since August 2012.
17. What is calorie and carb cycling?
I became quite lean when I started intermittent fasting, but I became even leaner when I started calorie and carb cycling, and introducing episodic carb refeeds. This approach prevents a decline in my metabolic rate when dieting for fat loss because I don't restrict my calories every single day. Therefore, my leptin levels are not stuck in "low gear" and my body doesn't have to try to conserve calories by slowing its metabolic rate. Plus, I get to eat carbs! Don't worry, I teach you carb refeeding and how to calorie and carb cycle in my Fat Loss Fast System.
18. What is flexible dieting?
Flexible Dieting is also referred to as “If It Fits Your Macros” (IIFYM). The IIFYM approach to diet allows for greater flexibility with your food selection because your focus is on the nutrients rather than the food source.
From my own personal experience, I can tell you I failed miserably following other people’s meal plans. The problem with meal plans is that you are forced to demonize all foods that are not on the plan, which can lead to micronutrient deficiencies and an extremely unhealthy relationship with food. Furthermore, with flexible dieting, you can select the daily treats you want (in moderation) and you don’t have to demonize carbs!
Please note that flexible dieting is not an excuse to try to squeeze in copious amounts of nutrient deficient junk food on a daily basis. If you follow this approach, micronutrient deficiencies will likely ensue. You will also run into issues with hunger because junk food is high in calories and low in fibre, so you won’t be able to eat very many Pop-tarts before you reach your calorie limit for the day. That is why I ensure 80% of my calories are nutrient-dense (“clean foods”) before I factor in any discretionary calories.
Note that I follow a high protein diet. Why? Protein provides satiety and helps me retain my hard-earned muscle when dieting for fat loss.
19. What supplements do you take Sara? Tell me more about BCAAs.
Timing is everything! There are supps you will take when fasted, and there are supps you will take when in a fed state.
Note: Always consult with your physician before you start taking supplements. This is especially important if you are taking prescription medications or if you are pregnant or lactating.
FASTED STATE: Training completely fasted is catabolic. BCAAs are a compromise: they may help stimulate muscle protein synthesis if ingested in a fasted state prior to fasted training.
FED STATE: I take fish oil and a multi-vitamin during my fed state. Vitamins A, D, E, and K are fat-soluble vitamins. They are absorbed into the body with the help of fats, which is why you should take multivitamins during your feeding window).
20. Will fasting catabolize my muscle?
- Don’t worry. You won’t catabolize muscle if you fast. According to a 2006 study in the Annals of Nutrition and Metabolism, up to 40 hours of total fasting does not stimulate catabolic processes that lead to skeletal muscle atrophy.
- If you are eating in caloric deficit, then you should be engaging in resistance training if you want to preserve your muscle mass.
- Muscle catabolism will inevitably occur during fasted training, but the increased anabolic activity post-workout seems to be a compensatory response to the increased catabolism that occurs during fasted training. People who are lean and active may opt to consume BCAAs during fasted training as it may enhance muscle protein synthesis.
- Any protein meals consumed within 24-48 hours of a resistance training session will contribute to muscle growth.
- Calorie adequacy during your eating window is paramount!
21. I have adrenal fatigue. Will fasting make this worse?
Adrenal Fatigue is not a real medical condition. There is no scientific evidence indicating that chronic mental, emotional or physical stress can damage the adrenal glands. You may see supplements being promoted that claim they are "proven to treat adrenal fatigue" and "reduce cortisol levels to minimize fat storage." Taking supplements to “treat” adrenal fatigue is very dangerous. In fact, they can cause your adrenal glands to stop working, which may put your life in danger. It can take months for your adrenal glands to recover full function after you discontinue exogenous glucocorticoids. If you are chronically stressed, then suppresing cortisol is not the solution to your problem. The solution to your problem is decreasing stress. ==> ALWAYS consult with your physician before taking any supplements, period.
22. Will fasting affect my thyroid?
Read my article, "Does fasting affect thyroid?"
23. Will fasting negatively affect fertility in women?
Read my article, "Intermittent Fasting & Fertility".
24. Sara, how do I get abs like yours?
Read my article: Get Awesome Abs in 6 Easy Steps
25. I need daily motivation!
Follow me on Facebook and Instagram @drsarasolomon for daily motivation!
26. Struggling to lose fat? Then read my articles:
- Put an End to Overeating
- Stop Failing at Fat Loss
- Can’t Stop Eating After Breakfast?
- Discipline
- Reasons You’re Not Losing Fat
- Carbs at Night?
- Lose Fat in 10 Easy Steps
- The Fatal Flaw With Diets
- Do You Eat Too Many Nuts?
- Fasting Podcast with Chalene Johnson
27. Feeling stuffed?
Read my article: Struggling to Eat Calories?
28. I'm bloated! Help!
Read my article: Beat Belly Bloating! 22 Quick Fixes for a Flat Belly
30. Do I have to "eat back" the calories I burned during my workout IN ADDITION TO my daily caloric requirement?
If your energy intake (ie. the calories you ingest) is greater than your energy output, then you will gain fat.
When you calculate your Total Daily Energy Expenditure (TDEE, which is the same as your maintenance level calories), this takes into consideration your Basal Metabolic Rate (BMR, which is your metabolic rate at rest) PLUS all the the calories you burn during the day from TEF (Thermic Effect of Food), volitional activity thermogenesis (ie. your workout) and NEAT(Non-Exercise Activity Thermogenesis).
Hypothetically speaking, let's say your BMR is 1260 calories and your TDEE (ie. maintenance level calories) is 1730. We already established the TDEE takes into consideration the calories your burn when you exercise, run errands, do chores, work on the job, digest your food, stay alive and subconsciously fidget. Therefore, if you eat your maintenance level of calories PLUS the calories your burn during your exercise session, then you will be eating in caloric surplus and you will store fat.
To calculate your calories and macros, use my free online calculator.
31. What about ______? (insert excuse)
Stop making excuses for why you might fail. Having a CONSISTENT approach to a SUSTAINABLE plan that suits your eating personality, goals and schedule … combined with a positive “can do” attitude is the secret sauce. As long as you are human and have consent from your medical doctor, you are a candidate to improve your health and fitness.
Here is my best advice: Don't rely on daily results for daily motivation. Instead, rely on consistency to motivate you. A maintainable approach is easy to consistently follow. Consistency = motivation.
If all of these people can do it, then so can you. Click here to see the Fat Loss Fast System testimonials.
33. How do I get started with intermittent fasting?
