One of the questions I often get asked is what blocks fat burn. I hear this on introductory calls all the time.  Potential clients tell me they were losing weight and suddenly they hit a wall.  They just can’t seem back on track particularly compared to like they were able to in their younger years. This is a very common phenomenon, especially for those of us over 40. 

I thought I would address this question today.  There are many factors that can affect fat burn. Most people think that it is most related to external factors like the amount and type of food you’re eating, or how much you’ve been exercising. Actually, often it’s more related to “internal” factors happening within your body that can block fat burn. 

I’m going to focus on those internal factors so you can have a better understanding and see if this is preventing you from achieving your weight loss goals.  There are two key hormones involved in supporting or preventing effective fat burn Insulin and Cortisol.  They act like twins in supporting or preventing you from effective weight loss. 

Insulin – The Glucose Blood Regulator

When we eat food, it gets broken down and some of it is converted into glucose. Glucose is like gasoline for the cells, it gives them power, it is only one source.  Insulin helps your body turn blood sugar into energy.  It also supports your body in storing extra glucose in muscles, fat cells and the liver for later use when your body needs it. If there is too much sugar or the receptors for insulin aren’t as efficient as they used to be, glucose isn’t effectively used and as a result gets stored as fat. This can happen as we carry weight for a longer period of time, as we age, or due to genetics. The result is a build up of it in the blood and it eventually will get stored as fat.

The Hybrid Car Model

The basis of the weight loss approach I use is based on intermittent fasting. You see there are two sources of fuel for cellular energy: glucose and ketones.  You may be aware of this if you’ve been following me or you may have heard about it from other sources.  To understand the difference between this approach and traditional weight loss check out my blog post, Which One for You? Traditional Weight Loss vs Intermittent Fasting.

Eating carbs particularly high glycaemic carbs will interfere, similarly eating too much food or too frequently will raise your insulin levels blocking fat burn.   Again, the key to this alternative energy source is for insulin levels to be low enough, long enough so that it will allow the body to switch fuels sources to the fat burn system.   

Cortisol – The Flight / Fight Hormone

The other hormone is cortisol. This hormone is associated with the stress response. Many factors can affect cortisol levels including the lack of sleep or level of stress we are experiencing.  The lack of sleep and / or high stress levels trigger the release of cortisol.  Even too much exercise can activate stress response thereby increasing cortisol. When cortisol goes up your body thinks it’s getting ready for fight or flight. It acts as a signal to immediately generate more fuel for the cells.  

Double Trouble

The result is the dumping of sugar into the blood to prepare for the fight or flight response … and that triggers the feedback loop “twin” hormone insulin to be increased (enhance the double trouble hormones). There is a direction connection between higher cortisol and increased insulin levels.  The perfect storm that will prevent you from losing weight. 

If you are struggling to lose or maintain your weight look at your sleep patterns.  Are there areas of your life that act as triggers for increased stress?  How much exercise you’re doing, if you are overdoing it, you may be putting your body into stress thereby raising cortisol levels.   Check out my blog on mindful meditation (Top 5 Benefits of Meditation for Improved Weight Loss Results), there are many stressors in life that we simply cannot avoid but can manage how we react to them. 

I have a really interesting example of this “feedback loop” from a client of mine.  I was using my BIA (Bio Impedance Assessment) device with her which measures fat, water, muscle mass, etc.  I was checking her body composition with each appointment (this was all pre-Covid-19) so I can see how much fat she was losing while ensuring she was maintaining muscle mass.  She had been losing a lot of weight, was feeling good, had lots of energy and had been experiencing high mental clarity for the first 3 weeks. Then one day she came in and said she was really tired, hungry and that her weight had stalled.  I did her body composition that day and sure enough she had hardly burned any fat burn at all. Her weight loss, which was a bit lower that week, was not coming from fat … that’s not healthy weight loss. She was on track with her food all that was fine but clearly something had happened.  I was thinking “cortisol” was the issue because her insulin levels were fine based on what she had been eating. So, I started asking what happened this week? How did you sleep? What about any stress?  She said it was the worst week ever, her dad had been diagnosed with cancer and her mom was very upset, as a result she didn’t sleep at all for almost two nights straight. 

I have to say it was quite amazing to see the impact of her stress resulting in high cortisol and the shutting down of her fat burning system.  That demonstrates how powerful these hormones are.  

When I work with people over longer periods of time, we’ll see this ebb and flow, there’s always a correlation. Think about insulin in terms of blood sugar levels. Think about cortisol relative to your stress level, amount of sleep and how you’re exercising. Work on strategies to manage your stress to bring your levels down, look at the amount of sleep you’re getting and cut back on your exercise if you are overdoing it (less is more). You may find that in and of itself may help with your weight loss.  

Hopefully this gives you some ideas and things to look at.  If you’re stuck there’s always a good reason why, it’s just a question of figuring it out. The hormones in your body really make a big difference to the whole process.  You can do everything perfectly as far as you’re concerned but your body may not be on the same page, it might actually be fighting you. I’ll have upcoming posts on strategies you can use to improve your sleep and manage your stress in these interesting times.  

In the meantime, reflect on how whether you think your body is working with or against your weight loss goals and track what is happening around you.  Becoming aware and drawing the connections is more than half the battle.