Why Diets Stop Working
Every fat-loss expert will tells you the key for success is calorie restriction and exercise. And there's no doubt these things work, especially for the beginner. But what if you're a fit person who's been following this advice, yet still struggles to lose body fat?
While research shows that weight loss and health may benefit from calorie restriction, there are also drawbacks to it. First, the weight you lose won't just come from stored body fat; there will also be a loss of muscle mass. And while resistance training may offset this to some extent, severe dieting will make it nearly impossible to hang onto all your muscle... and eventually stall out your fat loss efforts.
Why the heck does this happen? It's partly caused by a chronic stress response that changes how energy is produced, and decreases metabolism.
The Problem With Calorie Deficits
Most people expect fat loss to continue in a linear fashion, and when it doesn't, they make their diet even more extreme. They "diet harder" so to speak. They don't want to accept the plateaus or temporary rises in weight. But their expectations aren't realistic and the strategy of restricting calories only works against them.
Remember, the body decides where calories are allocated, and its energy expenditure is based on a hierarchy of needs. The energy required for resting metabolic rate (RMR) are always met first, as these are essential for survival.
What does RMR entail? It's the amount of energy – calories you burn at rest – including brain function. Your body has to work just to keep you alive, and RMR accounts for these basic functions. In fact, approximately 60-75% of your daily calories are required for these processes.
Any remaining energy is used for daily activities including exercise, recovery, and adaptation. When insufficient calories are consumed, the body needs to find a way of fueling these activities. Ideally this would come from the breakdown of body fat and release of fatty acids into the energy cycle. So while this system of lowering calories often works well in the beginning, over time it can diminish for a number of reasons.
Chronic Stress and The Preservation of Body Fat
First, the body is programmed for survival and is always trying to achieve homeostasis. This programming controls energy expenditure in a couple of ways. From an evolutionary perspective we're well designed to tolerate periods of low calories by using our body fat stores until food becomes available again.
However – and this is a big deal – when calories are reduced for significant periods, RMR itself decreases, enabling us to survive on fewer calories while preserving fat stores for as long as possible. It's a survival mechanism, and it'd be a lifesaver if we were facing a famine. But it's not such a good thing when we have an abundance of food at our fingertips.
So, when we voluntarily restrict calories to match RMR, we call on these fat stores to provide the missing energy at first. But once we get closer to our desired body composition and continue with diet and exercise, our genetic programming kicks in to ensure survival. It doesn't care that we're restricting calories on purpose.
The effect of chronic stress causes the preservation of body fat. This is achieved at the expense of protein stores from muscle mass, gut lining, and neurotransmitters. In addition to reducing RMR this can have consequences for digestion and absorption of nutrients, neurotransmitter function (affecting mood and motivation), and it may lead to fatigue. Ultimately, this complex process makes fat loss for the fit person more difficult.
How Do We Fix This?
Since everybody responds differently, and none of us are on the same diets or doing the same workouts, there's no simple answer. Raising calories would be a good first response along with making sure that the calories you consume are coming from nutrient-dense sources.
There are a range of ways to ameliorate the problem including calorie cycling or macronutrient cycling. In fact, sometimes even a short-term overconsumption can be effective.
I've used both workout cycling and calorie cycling with clients, with great success. In addition, increasing the number of rest days per week over the period of a month and then changing the macronutrient ratios on both exercise and rest days, may help depending on what's seen on testing results.
So there are many ways to progress again, but to continue losing fat, you have to think beyond calories and figure out why you may be hanging onto it despite your efforts. Remember also, that this process is dynamic, so what works for a while may not keep working. That's why it's important to make assessments regularly.
The thing is, there are certain stressors that'll make it difficult for you to lose fat no matter how strict your diet or how consistent your training. Fortunately there are tests available that can help you monitor how diet, exercise, and other factors are affecting you.
Let's take a look at the four biggest stressors that can bring your progress to a halt along with the simple assessments you can do at home.
Stressor 1 – Out of Range Blood Sugar
Using a glucometer to monitor your fasting blood sugar each morning will let you know if you're making energy through gluconeogenesis.
Cortisol is released in a diurnal (24-hour) rhythm. It's higher after waking, and then decreases throughout the day to an evening low. This rise in morning cortisol is called the cortisol awakening response (CAR). The purpose is to stimulate glucose production to ensure there's sufficient energy to start the day. However, there are many reasons for variations to this rhythm, which can be identified with testing.
If you're struggling to lose fat, monitoring fasting and post-prandial (after eating) glucose might help to identify the problem. The ideal range for fasting and 2-hours post-prandial glucose is 74-88 mg/dL (4.1-4.9 mmol/L). While it's beyond the scope of this article to discuss all the mechanisms for post-prandial elevation, the important point is that levels outside these ranges will affect your ability to lose fat. If these are elevated, it's important to investigate. Begin by taking a close look your diet, exercise, and other stressors such as sleep.
When fasting blood sugar isn't in range, it's unlikely to be due to excessive carbohydrates or extremely poor insulin control (overfed cells, insulin resistance, or poor first phase insulin response). The reason, which can be confirmed with blood tests, (called OAT and DUTCH testing) may point to what's most likely some form of cortisol dysregulation.
The cortisol awakening response is normal in the morning to get us up and going, and it does this partly by raising our blood sugars. But when these are raised excessively we need to figure out why.
Cortisol dysregulation/hypoglycemia are common problems in sleep disorders. These can be driven by a whole range of different stressors, but for the lifting and fitness population, inflammation from overtraining is one cause that you need to consider. Insufficient calories is another.
If the blood sugar is out of range two hours after you've eaten, then you'd need to investigate your diet. What's called the "first phase insulin response" happens within a couple of minutes of consuming food. This can be dysfunctional due to gastrointestinal issues or early signs of beta-cell problems. And it can be seen in a general way with blood glucose monitoring where the blood glucose stays really high in the first hour and a half after eating.
Another thing to consider is insulin resistance, though in a population which exercises a lot, there's a secondary insulin receptor that helps with glucose transport and it's turned on by exercise. This by itself is a good enough reason to keep lifting as you age.
The other reason it may be high is due to excessive carb consumption. This type of monitoring really can tell you if further investigation would be warranted, though not exactly what's going on since there are many nuances. So, if fasting blood sugar is out of range, then looking at stressors is important. If post-prandial blood sugar is out of range then look at diet.
Stressor 2 – Inadequate Sleep and Thyroid Function
If you're trying to lose fat, high quality sleep is essential. And this should scare you into bed early: Regular sleep loss depresses the immune system. Even as little as one week of inadequate sleep disrupts blood sugar to the level of a prediabetic.
The effects of stress and cortisol disruption often manifest as difficulty in falling asleep or problems staying asleep. Sometimes this is accompanied with a desire to eat before bed or food cravings during the night. Restoring sleep naturally, without the use of pharmaceuticals, is preferable since these act as sedatives, reducing all the benefits of proper sleep.
The underlying cause of sleep problems is stress of some sort. This may include psychological or physical stressors such as insufficient or excessive exercise. Other physical triggers include insufficient sunlight, overexposure to artificial light (like from a cell phone or computer screen), nutrient deficiencies, and excess caffeine or alcohol. These stressors alter the circadian rhythm, affecting cortisol and melatonin release.
But remember, if you've dieted yourself into a state of chronic stress, then raising calories may be an important first step here. For some people, women in particular, raising carbs in the evening can help with sleep and energy production in general by also improving thyroid function (in terms of the conversion of free T4 to free T3).
Free T3 is the metabolically active thyroid hormone. People often have normal thyroid function, but this conversion is subject to change, and can do so almost on an hourly basis. Thyroid function along with the interaction of all the other hormones, enzymes, cofactors, etc. helps provide the energy we need. It basically regulates the sense of fatigue we experience.
Women appear to be more susceptible to low free T3, particularly when they're eating fewer calories and insufficient carbs. Everyone is different and these things change over time – so carb tolerance fluctuates between people and within the same person over a period of time.
Stressor 3 – Gut Dysfunction
Gut issues are a major source of stress for the body. It's well documented that digestive issues can stall efforts to lose body fat. These may require testing and professional consulting from a specialist.
Think gut problems aren't a big deal? They're a huge deal. Proper digestion and the absorption of nutrients is essential for fat loss. The body is a complex chemical factory that can't function properly without the right nutrients available. So asking your body to perform when it's deficient is like expecting your car to run without oil. Luckily there are some basic ways to assess whether digestion is a problem.
The first consideration is the regularity and consistency of your bowel movements. These should be well formed with elimination at least once a day. Constipation and diarrhea are both red flags of digestive issues that need to be addressed.
If you experience bloating, excessive gas, or reflux, then it's likely you're having difficulty absorbing nutrients and may have bacterial imbalances or food intolerances. Taking antacids or other medications to alleviate these issues will make the problem worse. They're temporary fixes for deeper issues.
If your diet is low in processed foods and you suffer from these symptoms then testing for bacterial overgrowth, Candida, parasites, and other bugs may be necessary to identify exactly what's going on.
Food allergies and histamine reactions occur frequently when digestion and elimination pathways aren't performing well. Gluten and lactose sensitivity are common and may have genetic components. If you find yourself becoming itchy, getting hives, urticaria or suffering from other chronic skin conditions, that'll be another sign that you have bowel problems.
Yes, all these things indicate gut dysfunction. Lots of symptoms indicate problems: gas, bloating, even the excessive feeling of fullness. It's interesting how many people tell me they think those things are normal. So many fit, lean and otherwise healthy-appearing people have chronic gut issues. It's not something to brush off.
Stressor 4 – Derailed Recovery
Heart rate variability (HRV) is an excellent way to check your response to stress. There's considerable research on this topic and many devices available to do this.
HRV is the measurement of time between each heart beat, and this is highly variable. Since our response to stress activates the sympathetic nervous system, this will result in the release of cortisol and other hormones that increase heart rate and blood pressure.
When this happens, the time between each heart beat becomes more regular, improving your fight-or-flight ability. On the other hand, when we recover from stress, the parasympathetic nervous system is stimulated. This restores the healthy variability between each heartbeat.
This information tells us a lot about our recovery from training and stress in general. When our HRV is high, it's a green light that our nervous system is in balance between stress and recovery. When our HRV is low, this indicates a low tolerance to stress, poor recovery from exercise, and possible inflammation.
HRV can change on a daily basis. When used with other markers of well-being such as sleep, mood, and energy, this can be a great tool to plan workout intensity, recovery days, and nutrition needs.
There are a number of devices out there you can purchase to test HRV. Essentially these help determine your baseline and then they tell you when you're in sympathetic or parasympathetic dominance.
These are often color coded. So green means you're good to go, orange means you're needing some recovery – maybe an easier workout day, or some light mobility/stretching. Red means you need to take a rest day until you're back in green again.
When you go into sympathetic dominance, unless it's extremely high, usually backing off on the training or doing short easy workouts for a couple days will afford you enough recovery.
When you're in parasympathetic dominance the best solution is some proper rest for full recovery. Often the scores will slowly get higher and then suddenly plummet into parasympathetic dominance and this can be tricky to get out of. Interestingly, it often precedes the onset of flu or some other illness.
Test, Don't Guess
If you're cutting calories and exercising, but still struggling with fat loss, then a stress response may be the problem. Comprehensive testing can identify the underlying physiological adaptations that may be hindering your progress. Addressing these can improve your health as well as help you achieve your fat loss goals.
Related: The Two Faces of Cortisol
Related: A Calorie is Sometimes Not a Calorie
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