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Metabolic Health: How LCHF, Keto or Fasting Increase Energy & Fat-Loss

Imagine [Jane], a keto fan waking up on a Sunday morning, greeted by the aroma of sizzling bacon, golden egg omelet, and freshly baked coffee. It’s just another day for a metabolically flexible keto practitioner.

On a more serious note though, why would you want to be metabolically flexible? Training your metabolism to use fats for fuel comes with a myriad of potential health benefits. A non-exhaustive list includes higher energy levels, better insulin sensitivity, a sharper brain, and a thinner waistline. Not impressed yet? Well, let’s dive deep into it.

What is Metabolic Flexibility

Metabolic flexibility is the ability to switch between sources of fuel – specifically, the body’s ability to use fats [ketones] for energy instead of glucose. Mitochondria function plays a massive role in how efficient we are in hitting the metabolic switch.

Why is this important? Metabolic inflexibility makes one dependent on glucose. In such state, the need for reintroducing this short-lasting fuel [carbs] increases to sustain energy. Over time this leads to more rapid spikes and declines in blood glucose levels, contributing to poor glycemic control. This leads to metabolic dysfunction, potentially developing into insulin resistance and diabetes. (1)

The proposed benefits of metabolic flexibility include

  • stable energy levels
  • higher insulin sensitivity
  • faster fat-loss
  • greater mitochondria function
  • more optimal lipid profile
  • lower rate of inflammation and OS
  • slower rate of aging
  • lower risk of metabolic syndrome
  • better cognitive function and neuroprotection

Training the ability to use fat for fuel is crucial in times of glucose depletion. Once the body taps into fats for energy, numerous physiological processes occur, proven to improve metabolic health factors. These effects primarily depend on reduced glucose ingestion. The research we skim to support our thesis includes keto, fasting, LCHF, or caloric restriction, all of which share this element.


Being more metabolically flexible means a greater ability to burn fat for fuel, resulting in more stable energy, fat loss, sharper cognition, and anti-aging. Consequentially, metabolic health factors like insulin sensitivity and lipid profile can improve.

lchf benefits

Metabolism vs. Metabolic Health

To understand how skipping breakfast, munching more avocados, or eating less candy contributes to metabolic health and energy, we need to define three elements.

  • Metabolism
  • Metabolic Health
  • Glucose [Energy]

Metabolism is the way our body produces energy using calories, oxygen, and water. It’s the physiological processes that fill our battery with ATP to sustain life. Efficient metabolism creates more energy from fewer calories.

Metabolic health relates to the efficiency of our energy-creation mechanisms [metabolism] in producing energy. It’s defined by metabolic markers like insulin sensitivity, blood glucose, and lipid profile. Simply put, having optimal HDL/LDL levels, lower glycemic variability, and a lower % of visceral fat, covers it.

Glucose is the primary energy fuel for humans. It needs to be well-balanced for our metabolism to work properly. Spikes or sharp declines mean high glycemic variability, which is bad for us. Our ability to take glucose and use it for energy, or store it into glycogen quickly says a lot about our metabolic health.

The Physiology of Ketosis → Energy Switch to Fats

During periods of glucose starvation, which happens in keto, LCHF, or fasting, the body taps into fat for fuel. Once there’s no glucose left to use, the body secretes glucagon to break down glycogen to glucose. When glycogen is depleted, the liver starts breaking down fatty acids into ketones to fuel our energy. (2)

Back in ancient times, people would go without food for days. They’d eat animal fat and protein, occasionally some veggies, nuts, and berries, until they could find the next haunt. Sources say our ancestors ate about 10% of the sugars we eat today. So their reliance on fats assisted in maintaining energy for longer periods of fasting.

Insulin is the hormone responsible for transporting glucose into tissues [muscle and liver]. During ketosis, the levels of glucose are so low that insulin takes a break. In today’s glucose-fueled world, the pancreas of many is fatigued due to the constant secretion of insulin. The cells become numb [insensitive] and insulin doesn’t recognize glucose as well.

Once the metabolic switch activates [by reducing glucose consumption via keto or fasting], we hit a reset button on our [sugar] metabolism. The body breaks down fats and spares lean muscle, and insulin sensitivity is improved as a result. (3)

Metabolic Health → Insulin & Glycemic Control, Cholesterol

Metabolic health is the health of your metabolism, which involves a complex set of processes of converting food into energy. Key components of metabolic health are insulin sensitivity, energy levels, glycemic control, and lipid profile.

It seems that by reducing the frequency of glucose ingestion, ketosis-stimulating diets like fasting, LCHF, or ketogenic diet can improve several metabolic health factors.

Metabolic flexibility shows a myriad of potential health benefits, especially in people with metabolic dysfunction trending towards diabetes or obesity.

Research on fasting, keto, or LCHF shows benefits in

  • Improving glycemic control (4) (3)
  • increasing insulin sensitivity (5)
  • reducing body weight and waistline circumference (5)
  • higher energy levels and lower inflammation
  • lowering HOMA-IR risk or insulin resistance risk (5) (3)
  • reducing LDL, total cholesterol, and triglycerides (6) (7) (8)
  • greater satiety and higher HDL levels (9) (8)
  • improving cardiometabolic risk factors (10)

Producing the frequency of glucose ingestion by fasting or keto can improve numerous metabolic health factors like insulin and glucose levels, inflammation, and lipid profile.

Fat-Loss, Obesity

Although there isn’t a magical bullet for weight loss, ketosis-mimicking diets can greatly impact energy creation on a cellular level, which greatly affects fat loss.

The ability to create more ATP from fewer calories, and to learn to burn fat for fuel does wonders for reducing your waistline. Reduced inflammation, lasting satiety, stable energy, and hunger hormone balance are some of the reasons why.

To be clear, caloric deficit is the main proven way that works for weight loss However, for a long time, we know that all calories aren’t equal. Each calorie has its function in the body.

Excess glucose increases oxidative stress and inflammation, causing DNA damage, and glycation [poor glucose transport], which leads to metabolic [and mitochondria] dysfunction. (11) (12) (13)

Impaired insulin sensitivity and glucose metabolism directly link to metabolic syndrome, increasing the risk of obesity and diabetes. The cells become numb to insulin, glucose isn’t recognized as fast, and insulin blocks fat from being broken down. (14) (15)

Studies on keto and fasting show beneficial effects like reducing body mass index, body weight, fat mass, cholesterol profile, fasting insulin, and Homa-IR. (16) (17) (18) (19) Additionally, the balance between hunger-controlling hormones like leptin and adiponectin improves. (20)

Fun Fact

Weight loss with ketosis is a different game. It’s about cleaning the internal, energy-producing machinery in the body so we don’t get stuck wanting more food, but being unable to extract all the goodness [ATP] from it.

Energy [Stability] and Mitochondria Function

The reason why ketosis is the main weapon of numerous biohackers, is its ability to improve mitochondria function. These power cells are responsible for generating ATP or energy in our body using oxygen and fats, in a process called oxidative phosphorylation.

Better mitochondria function means more energy, faster regeneration, and longer lifespan. This is why the M-cells are the main target of the anti-aging industry.

The body of someone with metabolic syndrome or a metabolically inflexible person has poor energy-creation machinery. They’re higher on the spectrum of insulin resistance which alters mitochondria function, making them more dysfunctional. (21)

The conversion of triglycerides from adipose tissue to ketones during fasting is an important mechanism that activates this metabolic switch. As a result, AMP-activated protein kinase inhibits anabolic pathways and stimulates autophagy. This reduces damaged cells and dysfunctional proteins, thus improving mitochondrial function (20)

Inflammation and Oxidative Stress

Just the mere reduction and insulin secretion and improvement of cardiometabolic risk factors drops inflammation down.

  • Research in 109 subjects before and after 10 days of fasting has shown decreased lipid peroxidation and increased total antioxidant capacity in plasma. (22)
  • Numerous studies showcased the ability of fasting, exercise, and keto-mimicking diets to reduce circulating markers of oxidative stress and inflammation like IL-1β or TNF-α concentration. (23) (24)
  • The most studied ketone body, B-Hydroxybutyrate (BNB) has been shown to improve mitochondria respiration, thus stimulating the endogenous antioxidant systems in the body. (25)
  • Since overeating has been associated with high inflammation and metabolic dysfunction, it ties perfectly with our theory that short-term caloric restriction, fasting, or keto can hit the reset button.

Reduction of glucose intake [frequency or volume] can acutely reduce inflammatory markers which leads to reduction of insulin resistance and cardiometabolic risk.

Hit the Metabolic Switch – Tips

Primarily, metabolic flexibility is gained with the reduction of glucose ingestion [eating less carbs], extending the non-eating window [fasting], and increasing the intake of high-quality fats.

But becoming metabolically fit isn’t just a result of our diet, but other lifestyle factors as well. It’s about understanding:

  • how to eat, when to eat, how to combine foods
  • how caffeine, MCT, and other nutrients help us shift into ketosis
  • how training [HIIT vs. LISS] affects glucose and energy levels
  • how quality sleep and stress management techniques affect our energy

Once you take care of all these, a few extra hacks for our vitalscend readers are shown below:

  • Keto Breakfast
  • MCT Coffee
  • The MF Plate
  • Glucose tracking

Instead of skipping breakfast, one good hack to extend your “fasting” is to enjoy a ketogenic meal. While you technically don’t fast, you still get the majority of the fasting benefits, as fasting is a keto-mimicking diet. Eggs, pork bacon, and avocados can become your new friends.

Caffeine, when consumed in a fasted state can help us shift into ketosis faster. A good trick for the cognitive-needing brainiac entrepreneurs out there is drinking something called bulletproof coffee. High-quality coffee with MCT oil or grass-fed butter [or ghee], blended to a creamy perfection.

Another, more sustainable tip is to combine more fat and protein on your plate and reduce carbs intake. If you’re not into fasting, and keto is a wild stretch for your lifestyle, then this may be for you. Next time, instead of a full bowl of rice, pasta, potatoes, or any carb-loaded gem you crave, try adding more asparagus, broccoli, and mushrooms,… you get the point.

You can monitor your glucose levels to see how certain factors like diet, specific foods, stress, and poor sleep affect it. By doing so, you can see through actual data, how that punch of alcohol or all-nighter you pulled affected glycemic variability. Hopefully, this can teach us to make better decisions.


  • Metabolic flexibility is the ability to switch the utilization of fuels for energy, namely from glucose to ketones. This makes one more metabolically efficient, leading to higher energy levels, anti-aging, and sharper focus.
  • Tapping into fats for fuel comes with a myriad of potential health effects like improved insulin sensitivity, fat loss, glycemic control, and lower inflammation.
  • Fasting, caloric restriction, LCHF, or keto diets have very similar effects, as they all trend toward stimulating ketosis. So one of the best ways to improve metabolic flexibility [and health] is a nutritional shift of lower frequency and volume of glucose consumption.

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