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Our circadian clock system has a significant influence on our health and our sense of wellbeing. Circadian biology influences up to 80% of epigenetic expression including metabolism, hormonal function, repair and recovery processes, detoxification, and many more important functions. Optimizing circadian biology is crucial for optimizing lifespan and healthspan.

Our modern lifestyles can have a significant negative influence on our circadian clock system. We have a primary clock in our brain, specifically in our pineal gland, and we have many secondary clocks throughout organs and tissues. To the extent that we tune the primary clock properly and synchronize it with the other clocks, we can experience a more optimal state of health. Compromising circadian function accelerates aging, shortens your lifespan, affects your sense of wellbeing, and contributes to diseases.

The two primary influencers of our circadian biology are light exposure and the timing of eating. It’s important to try and optimize these two variables.

Light Exposure

The principles of optimizing circadian biology through intentional light exposure are quite simple. This can substantially improve energy and mood.

The first principle is to expose yourself to natural light soon after waking. This has to be outside and without wearing sunglasses. This cannot be achieved through a window or wearing sunglasses. It does not matter if it is cloudy or sunny, the photon energy of morning light will be detected by your retina and communicated to your brain. This sets your clock and influences the timing of hormonal pulses. As much as possible, try to get 15 to 20 minutes of natural light exposure outside within the first one to two hours after waking.

The next principle is to repeat that process within the last one to two hours of daylight. In the latter part of the day, when the sun is lower in the sky, the photon energy is different, and this communicates a message to your brain. The same rules apply, try to get 15 to 20 minutes of natural light exposure without sunglasses. Try to do this within the last one to two hours of the day.

The final principle is to try and maximize natural light exposure each day. Studies have demonstrated that our emotional health, our sleep quality, our brain health, and our eye function are improved by maximizing natural light exposure. This does not mean overexposing yourself and becoming sunburned or directly looking into the sun which could damage your retina. If you have a retina condition and have been told you need to wear darker glasses in brighter natural light, then you should follow those instructions. However, if that is not the case, you’ll benefit from spending more time outdoors. Try to get at least one hour of natural light exposure a day. This can be continuous or broken up into smaller segments. More optimal would be to get at least two hours of natural light a day.

Following these three principles results in a significant positive influence on circadian biology, energy levels, emotional health, and sleep quality.

Timing of Eating

The second most powerful influencer of circadian biology is the timing of eating. A major contributor to the increasing prevalence of metabolic diseases and chronic weight gain in our population is consuming calories within two to three hours of bedtime. It is critical that we try to minimize food or beverage calories within two, but preferably three, hours of going to sleep.

The timing of eating has a major impact on our metabolic health and the quality of our digestion.

The three primary principles are also simple to understand.

I mentioned the first principle above. This is the most important of these principles and it’s critical to get this right for all of us. As much as possible, avoid any form of food or beverage calorie within two to three hours of bedtime. It’s okay to have non-caloric beverages such as decaffeinated tea, sparkling water, or anything that does not contain stimulants or calories. But it’s very important to avoid all calories.

When we sleep at night, there are a number of important processes our body needs to accomplish. This includes repair and recovery, detoxification, cellular autophagy (cleaning up broken parts), and allowing our brain to detoxify and reset itself for another day. Our body will not initiate these processes unless we are in a physiological fasting state. We do not enter a physiological fasting state until at least three hours after our last calorie.

Therefore, consuming calories within two to three hours of bedtime, disrupts growth hormone production, and disrupts the timing of initiation of these very important processes. This means that when we wake up in the morning, our body has not been able to accomplish all the purposes it needed to during sleep. Over time, the biological deficits this creates accumulate and lead to diseases and a shortened lifespan. Also, evening snacking is a significant contributor to insulin resistance and weight gain. Typically, in the evening, people will consume foods and beverages that are less healthy for them including alcohol. It’s critical that we honor this principle most of the time.

The second principle is to try and delay the consumption of any food or beverage calories for at least one hour after waking. Once again, you can have non-caloric beverages such as coffee, tea, or sparkling water. You just need to avoid calories. Non-caloric sweeteners such as Stevia or monk fruit are also fine.

Typically, by honoring these first two principles, an individual would have three hours of fasting prior to bedtime, an eight or nine hour interval of time in bed, and an additional hour of fasting after waking. This will provide at least a 12-hour fast each night. This is very important for everyone. Studies have demonstrated that currently most individuals are only truly fasting for eight to nine hours out of every 24-hour period. This is a major contributor to the disease burden our population is experiencing.

The final principle is an extension of the first two principles. It involves the concept of time-restricted feeding or, as some would call it, intermittent fasting. This is limiting your calorie intake to a specific amount of time each day. There are many human studies that suggest an overall benefit to our health by utilizing time-restricted feeding.

The most commonly discussed pattern is a 16:8 ratio. That’s a 16-hour fasting window and an 8-hour feeding window. If you finished eating at six o’clock in the evening, you would not consume any calories until 10 o’clock the next morning. You would then consume all of your calories between 10:00 and 6:00 the next day. You could also use a 14:10 ratio or a 12:12 ratio.

Studies have demonstrated that those who use time-restricted feeding typically have lower blood glucose levels, improved insulin sensitivity, lower inflammation, and lower markers of oxidative stress. Also, for those who use a 14:10 or 16:8 ratio, they may lose weight and be able to sustain weight loss more successfully.

Some individuals will utilize longer fasting windows such as an 18:6, 20:4, or even a one-meal-a-day type program. These also demonstrate many of the health benefits discussed, but they do not appear to result in weight loss. This is likely due to people overeating due to hunger during the narrower feeding window. Also, it’s hard to get the amount of protein your body needs during a narrow window. When we consume protein, not all of the amino acids are utilized for protein synthesis. Some of the amino acids may be converted to glucose and used as energy and some are detoxified through nitrogen elimination pathways. For many of us, we can only assimilate 30 to 40 grams of protein at any given feeding period.

For my patients, I typically recommend a 16:8 or a 14:10 ratio. If you’re actively strength training and trying to build muscle, I prefer a 14:10 ratio so that you can begin to consume a form of amino acids earlier in the day. This can enhance protein synthesis in muscle cells.

An exception to this are individuals who have physically demanding jobs or have intensive fitness regimens working out multiple times a day and utilizing a lot of calories. These individuals will likely get the best result from a 12:12 ratio.

Whatever your feeding window is, 8 or 10 hours, you can consume two or three meals during that time. You should minimize snacking.

It’s important to make sure you distribute your protein throughout the feeding window. I start my feeding window with essential amino acids, fiber, essential fatty acids, and nutrient-dense powders with minerals. This means that I start my feeding window with minimal calories but a lot of nutrient density. You’ll have to figure out for yourself what’s the best timing for the consumption of calories. Your body will teach you when it prefers to consume its energy. But you need to distribute the protein throughout the day as much as possible.

These feeding principles apply to our foundational approach to nutrition. There are different types of fasts of different lengths for different purposes for our health. This only pertains to how you would eat on a consistent basis regardless of whether you’re utilizing an energy-neutral diet (maintaining your weight) or a low-calorie diet (attempting to lose weight). It’s very important to identify the timing principles that your body best responds to and stick to them consistently.


Calorie Cycling for Weight Loss

For individuals wishing to improve their body composition, I often recommend a calorie cycling approach. It’s important that we focus on the concept of body composition optimization and not weight loss. Ultimately, we want to focus on building up our lean body mass while losing unhealthy excess fat. Traditional diets focused on weight loss and resulted in losing both fat mass and lean mass which is not optimal for our health. Studies have demonstrated that focusing on building up lean mass is the most effective way to lose weight and to sustain that weight loss into the future without struggle.

Therefore, we’re more focused on building up muscle than we are losing fat. However, if we follow the right protocol, we will achieve both.

There are four foundational principles that must be applied for this to succeed. These are critical. The first is that you do have to create some form of energy, or calorie, deficit. You can improve your approach to nutrition and fitness and improve your health. However, if you wish to lose excess stored energy (fat), then you must create an energy deficit. This is always necessary. This can be achieved through a consistent low-calorie diet or calorie cycling.

The next principle is to make sure you follow the timing rules of eating discussed above. If you do not get the timing principles right, you may not improve your body composition even if you follow the other principles. Eating close to bedtime can sabotage your efforts.

The next principle is that you must get sufficient protein. Historical low-calorie diets did not focus on optimizing protein consumption. This causes the body to consume lean body mass and fat mass when you are calorie restricted. In addition, insufficient protein intake increases hunger, reduces exercise performance, increases fatigue, affects your mood, and affects critical body functions. It’s always important that you focus on getting enough protein in your overall approach to nutrition. There are times when you may lower the protein for specific longevity benefits, but generally speaking, it’s important that you maintain adequate intake of protein. Also, as we age, we need more protein not less.

Protein utilization refers to the percent of amino acids in a given portion of protein that are actually used for protein synthesis. Protein utilization is never 100% from food-based protein. Essential amino acids are not a food, they are a supplement, but they do provide amino acids for protein synthesis without calories.

If you are planning to lose weight through calorie restriction, you need a higher protein target than typical. Many studies have demonstrated that lower calorie and high protein diets are the most successful for losing weight while limiting the loss of lean body mass.

Finally, you’ll need to engage in some form of resistance training. If you’re not engaging in consistent resistance training, you will lose lean body mass.

The combination of calorie restriction, proper timing of eating, consuming sufficient protein, and resistance training will result in improvements in body composition. Provided that confounding variables (insulin resistance, hormonal imbalance, nutrient deficiencies, toxicant issues, others) have been accounted for, these principles always work for improving lean mass while losing fat mass.

Some individuals may already have a substantial amount of lean mass. They can focus on maintaining their lean mass while losing fat mass, but it is important that they still maintain their lean mass. Most people I work with need to increase their lean mass while losing fat mass.

Regarding protein intake, this should be individualized based on your genetics, your current state of health, and accounting for potential gut function issues. As a general principle, I recommend women to consume at a minimum 100 grams of protein a day up to 130 grams of protein a day. This can vary based on your height and current body habitus. One formula recommends consuming one gram of protein for every pound of ideal body weight. This would be your ideal weight, not necessarily your current weight. For instance, if an individual was 150 pounds, but they wanted to lose 30 pounds, and they considered 120 pound their ideal weight, they would at least consume 120 grams of protein a day.

In my experience, most women will do well with 100 to 130 grams of protein a day.

For men, I typically recommend 120 to 150 grams of protein a day. If an individual is very tall with a large amount of lean mass, they may need 180 to 200 grams of protein a day. It also depends on your goals for how much lean mass you’d like to add to your body. If you would like to add a substantial amount of lean mass, you’ll need to consume more protein.

Again, generally, I recommend women to consume between 100 and 130 grams of protein a day and men to consume between 120 to 150 grams a day.

If you are working with me in my program, I will have provided you a specific number for your protein target.

Calorie cycling is not necessary, but in my experience, most people improve their odds of success by using this approach. Calorie cycling simply involves eating a lower calorie diet anywhere from four to six days of the week and consuming a normal calorie diet one to three days of the week. Most of my patients will use a low-calorie diet five days a week and eat more permissively two days a week.

Generally, I recommend women to consider a 1200 to 1500-calorie diet on their lower calorie days. However, we must consider their metabolic rate, their current height and weight, and their overall calorie expenditure. For most individuals, a 1200-calorie diet will create a substantial calorie deficit. However, if you have physical limitations that impact your ability to engage in physical activity, you may need to use a lower number such as 800 or 1,000 calories.

For men, I typically recommend anywhere from 1200 to 1800 calories a day depending on their current metabolic rate, their level of physical activity, and their size.

So, for an individual, this approach would involve consuming 1200 calories five days a week and then perhaps 2200 two days a week. Or they may consume 1500 calories five days a week, and 2200 two days a week. If you’re working with me, I will have provided you with specific targets for you.

It’s important to understand that it can take time for the body to adapt to this. This is especially true if you have not engaged in a body composition improvement program in a long time. Your body will attempt to maintain its current state. Also, if there are factors that influence your ability to mobilize fat from storage (the principle of flat flux), a low-calorie diet may just make you very hungry, tired, and irritable. Therefore, you have to pay close attention to the signals your body provides you.

When you reduce your energy intake and create a calorie deficit while simultaneously increasing your physical activity, you are going to experience some hunger. That’s part of the process. Provided that you can manage the hunger, you should stick with the program. However, if you become severely hungry, exhausted, moody, experience poor sleep, have difficulty exercising, or become increasingly achy, you’ll probably need to eat more. It can take time for your body to adapt.

However, most individuals that I work with do quite well with the low calories providing they get enough protein. If you are experiencing intense hunger, but otherwise you feel okay, increase your protein intake. This will often help. In addition, hunger is influenced by your hydration status and mineral status. It’s critical that you focus on proper hydration and adequate mineral intake. I recommend drinking plenty of non-caloric beverages such as water, sparkling water, herbal teas, or others, and adding a pinch of good quality sea salt or some drops of trace minerals to your beverages. This will help to maintain your electrolyte balance and hydration status so that it does not cause you to struggle with this process.

Again, the principles are to create a calorie deficit, follow the timing principles of eating, consume sufficient protein, and resistance train. This protocol works every time if it’s properly applied.

The calorie cycling approach allows you to be more permissive with your approach to eating one or two days a week. This makes the process more psychologically tolerable. It does slow down the weight loss over time, but ultimately, you will succeed. In addition, calorie cycling is an approach you can use for the rest of your life.

Most of the people I work with decide to do this. They will typically maintain a very disciplined approach to eating with lower calories Monday through Friday afternoon, and then eat more permissively over the weekend. This allows their body to cycle between catabolic and anabolic states which is good for you if done properly.

Your body will tell you when you need to moderate this. Typically, once your body adapts to this process and your metabolic flexibility improves, you start to feel really good. Even while in a calorie deficit, you’ll find that you feel great in your workouts, you recover quickly, and your mood and energy are excellent. In addition, you’ll often find that you have minimal issues with hunger. This can go on for weeks or sometimes months. However, there are times where your body will signal that it needs you to eat more. Typically, this will be a significant increase in hunger accompanied by fatigue, a feeling of mental drowsiness, potential changes in mood, and a decrease in exercise performance. In addition, after intensive workouts, you may experience an increase in soreness.

It’s very important that you learn to read the signals your body is sending you. There will be times where you have the green light to eat less and train more so that you can add more lean mass while losing fat mass, and there will be times when you just need to eat more and have some rest days and accept that you’re not going to lose as much weight.

The ratio of days you use will depend on your lifestyle and what you tolerate. Obviously, the more days that you are low calorie, the faster you will lose weight. Also, you don’t have to calorie cycle. You can create a calorie deficit and carry it out for as many weeks as your body tolerates it. Provided that you’re paying attention to the signals we discussed, there is no issue with staying on a low-calorie diet. A sustained low-calorie diet will often be effective for someone who has a substantial amount of excess body fat to lose. For someone who has less fat to lose, a sustained low-calorie diet may cause them to experience some resistance within four to six weeks. Again, your body will teach you what it’s capable of doing.

Again, for your body to tolerate the stress of a low-calorie diet while resistance training, it is important that foundational health issues are addressed. It’s important that you’re optimizing your nutrient status, hydration and mineral status, detoxification capabilities, gut health, important cellular functions, optimizing hormonal balance, and the many other variables that influence our health. If you’re working with me, all these variables are being addressed.