Is Intermittent Fasting a Diet fad or return to a more logical eating style? There are so many diet trends. Even as a nutrition expert it becomes easy to brush past them as “just another pitch”. To avoid this, I remind myself I am a counselor, and as such I need to be prepared to field a variety of questions. I need to be able to promote or breakdown any concept that comes my way. So, a few years ago, when Intermittent Fasting (IF) came across my desk in a conversation, I decided to dive into the research. Initially unsure of the concept, I dove into the forum corners of the internet to learn what IF was, then like any good medical professional, I turned to the literature for supporting rationale. To my surprise, the concept held weight. Here is the who, what and why about what IF can do for the body.
The phrase “intermittent fasting” sounds intimidating to the average person. Our society has become so fearful of any level of hunger (or too excited by feelings of complete fullness) that the word fast often becomes synonymous with starve. IF is not starving. At baseline, it is a very intuitive concept: our body does not need food all the time. If we look back over human history, we can see that food abundance has only existed in the last 100 years, and food excess for the masses is only as recent as the 1950s and 1960s. Before these periods, most people had some level of food scarcity. That meant missing a meal occasionally or frequently. Once again our minds shift to the suffering of the great depression, or an image of a homeless person looking for a chance to eat. IF is not the same as those things. Instead, IF is the practice of shrinking the time in which you eat. There are 24 hours in a day, and ideally we are not eating, or in a fed state, for a majority of those hours. Keeping food in a 12 hour span is step 1 for any IF dieter. Why?
Without going into too much detail, every time our body eats, we secrete insulin. Insulin is a storage hormone, it signals our body to store. When we eat too often or during too long of a period, insulin gets secreted, and the levels rise in the blood. This leads to two things: increased appetite and further increased insulin. This is why snacking gets so out of control. We eat something small, it digests quickly, insulin spikes, the food stores, we get hungry again, eat, insulin spikes once again before the previous meals hormone secretion is gone. Insulin accumulates and over time our body becomes used to it. Just like an antibiotic, we need a higher dose to do the same thing. Our body produces more insulin, which makes us even hungrier and signals the body to store. This cycle leads to the grazing tendencies of many cultures. Want to perform a fun test? Walk down a busy city street. If there are a bunch of kiosks and storefronts selling snacks, chances are you will see higher rates of obesity than in cities where the focus is on main meals (snacking is absent).
To summarize what we just discussed: IF at its base is controlling the hours you eat to allow insulin levels to drop back to a normal baseline. This regulates appetite, and gets your body out of the “storage mode” it knows too well. For women, eating in an 8-10 hour span is recommended for weight loss. For men, 10-12 hours is usually a small enough window to find benefit. If you are an athlete, or performing a physically demanding event, these rules should not apply. The “intermittent” part of this concept is that it should fit your schedule. I find it helps my patients to either think about it as: break your fast 12 hours from last night’s dinner, or eat dinner within 12 hours of when you eat breakfast. Either way, it forces you to think about when you are eating, which is something we all need help with from time to time.
*** Mythbust *** Breakfast: In the US, the “Breakfast” meal is the meal we eat when we wake up. Everywhere else, and more accurately, it is the first meal of the day- the meal that literally Breaks your Fast! This can be 6a, 9a, 1p, etc. Whatever you eat first is breakfast. So, if your lunch meal is your first meal, it is also your breakfast meal. This is important. The comment “Breakfast is the most important meal of the day” is only true if you are talking about it as the first meal of the day. This is because the quality and balance of food is extremely important in regulating appetite. An easy example to consider is comparing someone who rolls out of bed, grabs a granola bar and a coffee and starts their day, to a person who gets up, drinks some water, gets ready, goes to work, checks some emails, then takes a break around 9 to heat up oatmeal with some nuts and berries in it. Who will be hungrier at lunch? Who is more likely to make a better choice at lunch? Because of the breakfast and lunch meal, who is most likely to raid the vending machine for some simple and sugary? The quality of breakfast matters more than the time it occurs.
The focus on quality becomes relevant to all our meals. I always tell my clients that snacks snooze your appetite, they delay the appetite to a later time, while meals satisfy. A focus on real food at key points in the day is extremely valuable. Our society has evolved from a 3 meal per day society into a snack all day society over the past 50 years. We can thank our busy schedules and the time demand that comes with hyper productive technology and automation. Unfortunately, these advances have led to a work force that sacrifices it’s short-term energy and long term health to meet the demands. The disappearance of minimally processed, filling meals at breakfast and lunch is closely correlated to the tendency to over eat at night, complain of cravings, energy dips in the afternoon and of course, snacking. Is correlation causation? Perhaps not always, but I guarantee many of you reading are seeing consistencies.
With the focus on quality comes the focus on spread of food. Once we keep our food in a set period of time, we want to make sure there is time between meals. This allows insulin to rise, fall and dissolve. This regulates appetite and most people notice themselves needing to eat less often immediately. That is the core concept of a breakfast, lunch and dinner. Snacks are meant to bridge gaps. They are not a daily need to entitlement. They are valuable to curb appetite until quality food can be consumed. They are useful for athletes or those participating in demanding physical feats. Most often, our meals should be our priority.
Once you have selected or identified the hours to keep your food in, an ideal spread of quality food to keep your body satisfied, you are ready to see the steady benefits of eating the way our body intended. Instead of following a meal plan that forces you to eat when you are full, or even worse a meal plan that has you counting the minutes to your next meal, IF allows your body to find a natural rhythm.
For those with high fasted insulin levels (lab draws and symptoms can confirm), the next phase of the intermittent fast is to pick 1-2 days per week and extend the fasted period. For the extended fast, if you normally eat in a 12 hour span, shrink food to an 8 hour span. This extension of the fast drops insulin levels further, and allows the body to get into an unfed state. Don’t worry, this is not something that “crashes” your metabolism. You are not skipping meals. You are controlling when you eat. Your body still has adequate food coming in, it is just spaced in a more practical way for weight loss.
***Let me guess, your personal trainer tells you that you’re going to wither away or lose muscle. Something to remember: bodybuilders and individuals building muscle want high insulin levels- they are extremely active, with high levels of muscle mass, so storage means additional growth of these tissues. Further, they do not have excess fat cells signaling storage into fat, rather they have excess muscle cells asking for energy. So, the lean and fit trainer that boasts about the 6 meals per day they eat- good for them, I do that too! There are definitely people who benefit from that, but many of the overweight and obese clients seeking our advice are looking to shed weight and adjust their hormones. For these people, the “eat more to lose” will often times lead to frustration. Additionally, our bodies have evolved over a long period of time, and humans have survived thousands of years of famines, droughts, and periods of scarcity. If the first thing our body did when we missed a meal was ate our muscle, we would not have survived the trials of time. Our body does not want to consume our muscle tissue. That is a last resort. It is worth noting however that our body does closely regulate muscle. It only keeps what it needs. So for the bodybuilder with an extra 40 lbs of lean mass, if it does not get used, the body will break it down. This is where the fear of muscle wasting comes from. Once again, advice that is relevant to a specific population, yet somehow made it to the ears of the general public. For those who do not have excessive muscle, fear not, your biceps are safe.
Another common concern that goes along with the fear of muscle wasting is that not eating will ruin your metabolism. Something that most do not understand is the metabolism is just a title for the total burn of the body. Our cells and organs use energy to survive, heal, reproduce and function daily. Our heart beats, our brain thinks, our nerves conduct, our cells divide. These events require energy and produce heat (measured in calories) as a byproduct. While it is true that out metabolism varies (+/- about 40% on any day), fasting does not lead to permanent reductions in metabolic rate, especially when compared to standard caloric restriction. Eating less in general reduces metabolism, but with IF, you are not necessarily eating less. Many times, you are simply eating in a more natural, regulated, and intuitive way, which is quite beneficial. Remember, there is a difference between the person that skips meals thanks to stress all day then settles for low quality food and the intermittent faster than plans when to eat and focuses on the quality of food to regulate insulin and other hormones.
Just like every dietary concept, this is not a one size fits all. Not everyone should do this, and not everyone benefits from this concept. During consultations, my team evaluates our patients extensively before building a program. This is a tool we use for those with hormonal barriers to weight loss. The people that are maintaining or gaining weight on low calorie diets are the most common population. On the contrary, IF is rarely a recommendation you see in the lean and fit, the athletes, the hypermetabolic, and those losing weight for the first time. Our body is a complex system, and IF is just another key that can help some unlock their puzzle of optimal health.
- Water, Unsweetened Tea, Black coffee are okay in the fasted state
- No artificial sweeteners during fasted state
- Fasting in the morning is often the easiest time (our breakfast sparks our appetite) – it is easier to stay fasted once fasting.
- Extended fasts are easiest on days with less physical activity and days with mental stimulation. A busy morning flys by.
- If you are exercising to perform- do not fast on those
- If you are exercising to lose fat (slow and steady cardio) you can fast
- Fasting does not need to occur daily, look at your schedule and listen to your body
- Ask to have your fasted insulin levels checked- it is not a common lab to order