Food Freedom Friday Edition 290 - Weight Loss & Oxidative Priority

The human body can burn many different fuel sources – glucose, glycogen, amino acids, lactate, fat, ketones, and many others. In fact, you’re always burning a mixture of them depending on what you’re doing and what’s your metabolic status.

Oxidative priority describes which fuel substrates the body prefers to burn at any given moment and how it affects your metabolism in general. To ensure survival, you need appropriate allocation and use of resources. Otherwise, you’ll end up missing out on key opportunities and/or will just starve

The #1 oxidative priority is alcohol because it’s a toxin the body tries to get rid of ASAP. That’s why it’s known that ethanol inhibits the utilization of other macronutrients and causes insulin resistance. Your body is suppressing the oxidation of fats as well as carbs when drinking alcohol until you are no longer intoxicated.

Furthermore, the thermic effect of food (TEF), or how much of the food you eat gets burnt off as calories, depends on not the timing but more on the macronutrient ratios of the meal. Protein has the highest thermic effect.

Studies also show that how often you eat does not significantly impact how many calories you spend on digestion. Eating 6 small meals is not going to fire up your metabolism because eating 2 large meals will have the same thermic effect of food. 

Personalized Implications

You have very little room to store alcohol or ketones.  They are more volatile than the other fuels, so they have to be used as the highest priority – they are utilized and metabolized before anything else.

Most of the protein you eat is used for muscle protein synthesis and other critical bodily functions.  While ‘excess protein’ not used in for muscle synthesis can be converted to energy (ATP), this usually only happens when you are not eating enough carbs and fat to provide adequate energy, so your body turns to the protein in your diet or the protein on your body (your muscles and lean tissue).

Excess protein (anything that is not required for muscle repair and other bodily functions) can be excreted in the urine if it is not used for energy.  Again, this is rare in people with healthy kidneys because. A little bit of “labile protein” circulates in your bloodstream, but not much. 

Protein has the highest thermic effect. 20 to 35% of energy is lost in the conversion to usable energy, so your body has to work hard to convert it to usable energy.  You would rarely consume ‘excess protein’ and would prefer to get energy from fat and/or carbs, so higher protein foods tend to be more satiating.  

Your body has some limited capacity to store glucose in the liver, blood and muscle, but not a lot compared to your body fat stores.

If you fail consume an ‘adequate’ number of carbohydrates, your body will work to keep your glycogen stores topped up by converting protein to glucose (through gluconeogenesis), so you always have some when you need it. 

You have some fatty acids in your bloodstream to use for fuel but a very large capacity to store excess energy that you do not use. 

The amount of energy your liver drip feeds into your bloodstream from day to day is tiny compared to the amount of energy you store as fat. 

Some people can hold a tremendous amount of fat in their adipose tissue before it backs up and overflows back into their bloodstream.  Meanwhile, due to genetics and other factors, other people have a much smaller ultimate capacity in their fat cells before it overflows, and they develop diabetes and other downstream inflammatory conditions.

The bottom line is that you need to deplete the higher priority fuels before your body uses that unwanted fat on your butt and belly.

Ketosis And Oxidative Priority

being in ketosis changes the hierarchy of oxidative priority, making your body use fat and ketones as a fuel source instead of glucose. As a result, your body experiences higher rates of fat oxidation, thus being able to tap into its fat stores more easily. To lose weight you still need an energy deficit but the oxidative priority shifts more towards burning fat.

Eating fat in the presence of other macronutrients with a higher oxidative priority may result in higher fat storage due to decreased fat oxidation. The body is basically burning the higher priority fuel sources - alcohol or carbs - first before it starts to burn fat. This explains why mixed diets tend to be more obesogenic and energy dense.

Weight Loss And Oxidative Priority

Knowing the oxidative priority of different foods is a great way to choose the type of fuel you would like to burn. This can support optimizing training, recovery, and fat loss. A few considerations when weight loss is your goal include:

Avoid drinking alcohol and eating at the same time. As you are now aware, alcohol inhibits the oxidation of other fuels. You should limit your alcohol consumption to a maximum of a few drinks per week and ideally not eat too much food with it. If you do drink, focus on higher protein and low-fat foods to prevent fat storage.

Eat high protein. Protein has the highest thermic effect of food and is relatively high on the list of oxidative priority (compared to fat and carbs). The best thing about protein is that it keeps you closer to fat oxidation than carbs because it raises your basal metabolic rate. When eating carbs immediately kicks you out of ketosis and suppresses fat oxidation, then protein keeps you somewhere in the middle. It also promotes muscle growth and satiety. Generally, aim for about 0.7-1.0 g/lb of LBM.

Eat carbs based on activity. If you’re not exercising then there’s not a real reason to be eating a lot of carbs either. For optimal fat oxidation you should eat carbs around your more intense workouts so that they would be stored as muscle glycogen as opposed to fat. Carbs around training also help to build muscle.

Avoid combining fats and carbs. Combining fats and carbs suppresses fat oxidation, causes insulin resistance and can promote overeating. That’s why it’s better to either do a low-fat high carb diet or a low carb diet. Combining fats and carbs is more of a concern if you’re eating at a calorie surplus and you can probably get away with it when eating at a calorie deficit although it is still far from ideal.

Intermittent Fasting. Time-restricted eating increases fat oxidation at least during some parts of the day. This promotes keto adaptation and conditions the body to use fat for fuel. Increasing autophagy will also encourage the turnover of fat cells and lipolysis. Intermittent fasting already suppresses insulin and helps to stick to a calorie deficit but it also promotes lipophagy the oxidation of fat cells by autophagy. I’m also taking digestive enzymes during the fasted state to increase the breakdown of triglycerides and lipids. There’s also compounds like betaine HCL and dandelion root that support lipophagy. 

Eat high satiety meals. In order to maintain a calorie deficit without rebounding, you have to focus on eating high satiety foods with more nutrient density and satiety. Generally, those foods tend to be high in protein and fiber. Empty calories like oils and added fats are just extra calories that may increase fat oxidation from the meal but they won’t make you lose fat.

While you don’t have to jump to a super high protein extreme, cutting back on the easily accessible energy from both carbs and fat (while still getting adequate protein and nutrients) is THE SECRET to ensuring fat loss from your body.