How Does Fasting Work
Our bodies put in a lot of work when it comes to processing the food we eat to provide us a consistent source of energy.
When we eat food is broken down into macro and micronutrients via digestive enzymes. Carbohydrates like rice and starchy vegetables get broken down into glucose to be absorbed into our bloodstream and utilized for immediate energy with the help of insulin.
When our cells don’t use all of the glucose from the food we eat it gets stored in our liver and muscles as glycogen. And when in a calorie surplus, any leftover fuel gets store in our fat cells, as fat.
In-between meals, and when we first start fasting as long as we aren’t snacking, our body will utilize glycogen and some stored fat for energy. But once our glycogen stores are depleted our body will begin to break down more fat for fuel .
Prolonged fasting will eventually prompt our body to experience ketosis and metabolically switch to breaking down fat as fuel using stored fatty acids instead of glycogen for energy .
Basic Facts On Intermittent Fasting
To keep it extremely simple, intermittent fasting is a dieting plan focused not so much in what you eat, but when you eat. It is simply referring to a pattern of eating. Not the contents of what you eat. This is why sometimes, calling it a diet can be a bit misleading.
Intermittent fasting lifestyle involves adopting an eating pattern. This pattern cycles between two periods. The eating period, and the fasting period. We will explore the attractiveness of this pattern in a bit, but for now, you need to know there is no one-size-fits-all plan.
From beginners to novices, to the well experienced, there are myriad of ways to plan out an IF diet. We will however break it down to some generally popular patterns, to keep things even more simple.
Whatever method you end up choosing is up to you. The reasons for each selection varies with each individual. Depending on your goals and your lifestyle, its up to you to figure out your favorite plan. You may even move from one plan to another as you reevaluate your goals.
Does Intermittent Fasting Have Different Effects On Men And Women
The quick answer is: yes, Intermittent Fasting can affect men and women differently.
Anecdotally, we have many women in our online coaching program that swear by Intermittent Fasting, while others have had adverse effects.
Lets dig into the science and studies.
A recent PubMed summary concluded thatfasting can be prescribed as a safe medical intervention as well as a lifestyle regimen which can improve womens health in many folds .
Now, in that extract, many of the studies cited are focused on specifically calorie restriction , and they also say that future studies should address this gap by designing medically supervised fasting techniques to extract better evidence.
Digging into the PubMed Archives brought me to the following conclusions :
One small study resulted in the following: Glucose response to a meal was slightly impaired in women after 3 weeks of treatment, but insulin response was unchanged. Men had no change in glucose response and a significant reduction in insulin response.
Another small study studied the effects on their menstrual cycles after a 72 hour fast which is significantly longer than any fast recommended in this article: in spite of profound metabolic changes, a 72-hour fast during the follicular phase does not affect the menstrual cycle of normal cycling women..
Precision Nutrition a great resource recommends not attempting Intermittent Fasting as a woman if:
- youre pregnant
- you dont sleep well
- youre new to diet and exercise
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Adjust Your Workout Routine
When just finished working out, eat all of your calories in one meal and then consume small meals every 2-3 hours after that until dinner time. If you plan on working out later in the day, break your fast by eating half of what you would normally eat at lunchtime and then move into three smaller meals throughout the day, with each serving size depending upon how long ago you worked out.
You can do intermittent fasting in many ways to maximize your results. It is crucial to adapt your workout routine around the fast. Do some exercise first thing in the morning when you have the most energy, and be mindful of what types of movement to do during the day.
Be careful with your exercise routine if youre not fueling your muscles well enough, consider lower-impact workouts on fasting days, and drink a lot of water.
Could Help Lower Cholesterol
Your cholesterol might also improve after intermittent fasting when consuming a healthy diet during your non-fasting periods.
Better lipid profiles have been found after intermittent fasting including lower overall cholesterol, lower LDL , and lower triglyceride levels in healthy and overweight populations .
The majority of studies investigating intermittent fasting’s effects on cholesterol have focused on those fasting for Ramadan, so intermittent fasting may be an effective dietary method to improve your cholesterol, but further studies are needed to explore the differences in short-term vs long-term metabolic changes associated with fasting. .
If you’re concerned about high cholesterol try adopting healthy lifestyle habits like incorporating exercise and a diet low in saturated and trans fats, and rich in high fiber foods.
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How Circadian Rhythm Plays A Role
One of the ways intermittent fasting seems to work is by capitalizing on our natural circadian rhythms, also known as our sleep-wake cycles.
An excellent way to reduce stress on our body is by allowing it to follow its natural circadian rhythm, or more simply put, having a regular sleep schedule, explains Merrill. When this rhythm is interrupted, it negatively affects our energy and appetite levels as well as our gut health. It decreases the presence of healthy gut bacteria and increases susceptibility to inflammation and irregularity in bathroom trips.Interestingly, the gut also has its own circadian rhythm. All the different types of bacteria in the gut have different responsibilities, and when disrupted, this can cause mutations or growth of dysfunctional bacteria, says Allison Thibault, RDN.
You naturally fast while youre asleep, which helps your gut keep its own circadian rhythm going. Some believe prolonging the fasting period, as you would with intermittent fasting, can help capitalize on those effects.
Intermittent fasting is not required to allow your body to follow its natural circadian rhythm, Merrill points out. But some people sleep better if they stop eating a few hours before bedtime. While practicing IF, you may forgo a bedtime snack, giving your digestive system a break and possibly aiding sleep, says Merril. That, in turn, could improve your gut health. This isnt proven for everyone, but is a common report.
Can Lead To Eating Disorders And Disordered Eating Tendencies
“Only eating between certain time windows may limit many opportunities for eating, and therefore lead to the underconsumption of food and calories. Some people may develop eating disorders or disordered eating tendencies due to the stress and hyperfocus on food and calories,” says Schlichter. “Furthermore, having someone eat more just because it’s ‘time to eat’ can lead to overeating and bingeing within the designated eating window, and ignoring all bodily cues of fullness. They may begin to view food as less important and more restructured, and may consciously or unconsciously undereat for their body’s needs, leading to physical, emotional, and hormonal side effects, such as the loss of menstruation, hair loss, and dysregulated blood sugars.”
It Can Be Hard To Maintain
“Keeping up with this strict way of eating is difficult, mainly because our bodies aren’t wired to only eat within small intervals in our society today. With many social events occurring at night and often within non-designated eating times, many people are not able to stick to these restrictive guidelines for eating,” says Schlichter. “Furthermore, they feel hungry throughout the day when they aren’t eating and aren’t able to gorge all of their calories during designated times. Once a person resumes his/her normal way of eating, they’ll usually gain the weight back, but more so, have to work on rebuilding their relationship to food and learning to trust their body again to give them signs of hunger to eat, and cues for feeling fullness.” To build a better relationship with food, you might consider trying these 11 Mindfulness Hacks to Eat Less, According to Experts.
What It Doesto The Body
There are some significant changes that happen to the body, and these occur in your body in a good way. These effects occur both physically, and mentally, and in both cases, the effects are quite positive. More on the reason theyre beneficial later, but for now, lets focus on the effects of this practice.
- Intermittent fasting changes your human growth hormone levels. Those levels shoot way, way up, increasing to about 5 times the level it used to be.
- Your genes express differently, as they effectively become changed by your fasting lifestyle. They begin do this for instance, by metabolic switching.
- Cells begin a repair process, that is usually triggered by fasting. When you fast, your body begins to digest, and dispose of old protein buildup that is usually stored in the body.
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What Are The Negative Effects Of Intermittent Fasting
In my own experimentation with Intermittent Fasting since 2014, I have found very few negative side effects with Intermittent Fasting.
The biggest concern most people have is that Intermittent Fasting will lead to lower energy, focus, and the holy crap I am hungry feeling during the fasting period and ruin them.
People are concerned that they will spend all morning being miserable because they havent consumed any food, and thus will be miserable at work and ineffective at whatever task it is they are working on.
The following are my thoughts and experiences, and your results may vary:
Yes, the initial transition from EATING ALL THE TIME, to intermittent fasting MIGHT be a bit of a jolt to your system it was for me.
However, once I got through the transition after a few days, my body quickly adapted and learned to function just as well only eating a few times a day.
Although I fast for 16 hours per day with no issues, the following might help assuage your fears that skipping breakfast will cause your body to eat itself and your brain to implode:
After 48-hours of fasting in a recent study , cognitive performance, activity, sleep, and mood are not adversely affected in healthy humans by two days of calorie-deprivation. Youll be fasting for far less time than that.
So why do I feel grouchy and lethargic when I skip breakfast?
If you eat breakfast every morning, your body expects to wake up and eat food.
Is Intermittent Fasting Safe Long Term
Intermittent fasting plans have the potential to backfire tremendously especially if your goal is to lose weight. Fasting can lead to nausea, dehydration, and even weight gain over time. There hasn’t been enough definitive research that has effectively looked at the long-term effects of fasting on metabolism. You may also eat more than you thought you would during your days or times of “feasting” too. In his review, Mattson advises that anyone attempting to fast should gradually increase the duration and frequency of their fasts over longer periods of time and that physicians should closely monitor your progress.
Eating real, nutrient-dense foods on a consistent basis fuels us physically, mentally, and emotionally. So if intermittent fasting works for you, go for it! But if it makes you feel anxious, depressed, or isolated in any way, it may not be the best plan for you personally.
Plus, I’d be remiss to mention who should absolutely not dabble in this eating style: Anyone who’s previously struggled with an eating disorder or experienced disordered eating behaviors, or if you’re immunocompromised, pregnant, lactating, or on insulin, oral hypoglycemic, or food-metabolizing medications. No matter who you are: Always check with your doctor before starting any new diet plan especially one that includes fasting!
What Artificial Sweetener Breaks A Fast
Artificial sweetener refers to certain substances that give the same sweet effect as your natural sweeteners such as sugar and honey. They are produced in the lab, and some of them have zero calories, while others are loaded with them. To know what artificial sweetener breaks a fast, you must know its caloric content.
At the same time, you need to be sure if the artificial sweeteners of your choice will give you the required result or not. Some of the artificial sweeteners that wont throw you out of the fasted state are: saccharin, aspartame, sucralose . However, if you go for artificial sweeteners like sugars of alcohol with high calorie content they will break your fast.
Are There Any Potential Downsides To Intermittent Fasting
IF has been shown to improve the quality of life for many people, but there are some downsides to intermittent fasting. There is a risk of developing hypoglycemia, which can result in dizziness, lightheadedness, and confusion.
Some people may experience stress, anxiety, or irritability when trying IF. Furthermore, suppose you have a history of eating disorders. In that case, it is not recommended that you try intermittent fasting because there are risks involved with certain types of IF that could trigger these behaviors in an individual who has already been struggling with them.
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Here Are The Main Health Benefits Of The Intermittent Fasting Diet:
- Weight loss: As mentioned above, Intermittent Fasting can help you lose weight and belly fat without having to consciously restrict calories.
- Insulin resistance: Intermittent Fasting can reduce insulin resistance, reduce blood sugar by 3-6% and fasting insulin levels by 20-31%. This will protect against type 2 diabetes.
- Anti-inflammatory: Some studies suggest that Intermittent Fasting can reduce bad LDL cholesterol, blood fats, inflammatory oils, blood sugar and insulin resistance. All of these are all risk factors for heart disease.
- Cancer: Some studies show that Intermittent Fasting can help prevent cancer.
- Brain health: Intermittent Fasting increases the concentration of a brain hormone called BDNF, and may support the growth of new nerve cells. It may also protect against Alzheimers disease.
- Anti-aging: Intermittent Fasting can extend the life of mice. Research shows that mice that follow this diet live 36-83% longer!
So Is Intermittent Fasting As Good As It Sounds
I was very curious about this, so I asked the opinion of metabolic expert Dr. Deborah Wexler, Director of the Massachusetts General Hospital Diabetes Center and associate professor at Harvard Medical School. Here is what she told me. “There is evidence to suggest that the circadian rhythm fasting approach, where meals are restricted to an eight to 10-hour period of the daytime, is effective,” she confirmed, though generally she recommends that people “use an eating approach that works for them and is sustainable to them.”
So, heres the deal. There is some good scientific evidence suggesting that circadian rhythm fasting, when combined with a healthy diet and lifestyle, can be a particularly effective approach to weight loss, especially for people at risk for diabetes.
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The Proposed Health Benefits Of Intermittent Fasting
When it comes to weight loss, there are two thoughts behind why IF has the potential to work. The first: Periods of fasting produce a net calorie deficit, and so you lose weight, explains Rekha Kumar, MD, a specialist in endocrinology, diabetes, and metabolism at the Comprehensive Weight Control Center at Weill Cornell Medicine and NewYorkPresbyterian in New York City. The other concept is more complex: This approach may prevent whats called the plateau phenomenon from happening, she says.
You may remember the famous, so-called Biggest Loser study, published in August 2016 in the journal Obesity. The researchers followed up with participants after six years, and despite the initial impressive weight loss, they regained most of the weight, and their metabolic rates had slowed, such that they burned far fewer calories than would have been expected.
Though more research is needed on the safety and effectiveness of IF, one of the touted benefits of this approach is it may prevent this metabolic sputtering. Most people who try diet and exercise to lose weight tend to fall off the wagon and regain weight. Hormones that promote weight regain, like hunger hormones, are kicked into full gear, and the thought is that IF may be a way to prevent this metabolic adaptation from happening, says Dr. Kumar. Normal periods of eating in IF trick your body into losing weight before the plateau happens.
Stay Away From Sweeteners
Sugar-free light drinks are popular not only for diets but in general. Nevertheless, it is these drinks that prevent success in intermittent fasting.
Contrary to the advertising message, zero sugar does not stand for fat burning in reality.
Moreover, they erase gut bacteria that are a guarantor of our health .
Precisely because sugar-free drinks hardly increase blood sugar levels, they trigger cravings for sweets in the brain. Therefore, sweeteners make people hungrier than conventional sugar .
It appears that people who consume diet products like water are more often overweight, which is a proven fact.
Accordingly, researchers at the University of Texas at San Antonio found that consuming light beverages increases the likelihood of weight gain by 47 percent .
During the fasting period, fluid intake is essential. However, it should be limited to water, mineral water, tea, and coffee without additives.
On the one hand, diet sodas break the fast. On the other hand, they will push your goals further away, even in eating periods.
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