07/07/2020 10:31
Understanding energy balance is so important when it comes down to changing body composition.
Energy balance is simply the interplay between energy we consume through food and liquids and the energy we expend.
Hormones play a huge role in the energy balance equation. The two major players here are leptin and ghrelin.
Let me explain why these are so crucial.
When leptin and ghrelin are produced they travel to an area of the brain called the hypothalamus.
The hypothalamus is a bit like the organisation centre of the brain; your body creates signals in response to things going on in your body and around you and these signals are sent to the hypothalamus.
The hypothalamus integrates and sorts through these thousands of signals and generates actions that make sense in response to keep us alive, like eating when we are hungry.
What is ghrelin?
Ghrelin is a hormone that’s released from the stomach and small intestine and travels in your blood to the hypothalamus. It is often called the ‘hunger hormone’ because its levels rise in the absence of food triggering us to find food and eat; levels then fall again after you eat.
When you aren’t eating enough to maintain energy balance, whether intentionally or not, ghrelin levels will be higher, likely creating cravings and testing your will power to override the bombardment of ghrelin signals to your brain and not eat the whole cake that’s been left out for Karen’s birthday.
Back in the day before supermarkets existed, this hormone was actually vital to survival because it not only creates hunger signals but actually allows us to have the capacity to go and hunt and gather our food even when we have no real energy from food.
It does this by creating a stress response in the body (releasing our stress hormones cortisol and adrenaline) to make you feel alert and it causes blood sugar levels to increase to provide energy to your brain and muscles to take action!
It even has an effect on the other side of the energy balance equation. In times of low energy intake, it reduces your metabolic rate to conserve energy (reducing energy output).
Summary of ghrelin
Regardless of current body fat percentage, ghrelin is released when energy intake is low and energy balance becomes negative, it is our body’s protective mechanism in response to starvation.
What is leptin
Leptin is the other key player in this hormonal control of energy balance. Leptin is produced by our fat cells and travels to the hypothalamus to inform the brain how much body fat we have stored and if it’s going up or down.
Leptin signals to the brain, in particular to an area called the hypothalamus. Leptin does not affect food intake from meal to meal but, instead, acts to alter food intake and control energy expenditure over the long term.
Factors promoting leptin secretion
- Excess energy stored as fat (obesity)
- Overfeeding
- Glucose
- Insulin
- Glucocorticoids
- Estrogens
- Inflammatory cytokines, including Tumor Necrosis Factor-α and Interleukin-6 (acute effect)
Factors inhibiting leptin secretion
- Low energy states with decreased fat stores (leanness)
- Fasting
- Catecholamines and adrenergic agonists
- Thyroid hormones
- Androgens
- Peroxisome Proliferator-activated Receptor-γ (PPARγ) agonists†
- Inflammatory cytokines, including Tumor Necrosis Factor-α (prolonged effect)
To maintain energy balance and a healthy body fat percentage leptin and ghrelin both work on the hypothalamus but they work by fighting each other for their spot.
When we are in a positive energy balance, leptin levels rise and fight off more of the ghrelin. The higher the body fat percentage the higher the leptin and the less ghrelin gets a look in. This means our metabolism stays firing to increase our energy output and our hunger spikes are dampened to reduce our energy intake.
But when we are in a negative energy balance and lose body fat, leptin levels fall and ghrelin can take hold on the hypothalamus making us hungry to go and hunt for food!
So if this system is so great why do we struggle to stay in energy balance and maintain an optimal healthy body fat percentage?
There are a whole host of other factors that influence our energy balance equation.
First and foremost, we don’t just eat because we are hungry! As humans we eat for so many different reasons from emotional to social and even environmental. Overeating is easy in our new environment full of ‘extreme reward foods’ which are high fat and high sugar that light up the reward centre of our brain like a Christmas tree, I’m thinking Krispy Kreme here!
But under eating is also common with our hectic work and on the go lifestyles, time can just pass by and before you know it you haven't eaten for 7 hours!
Energy balance is a constantly moving see saw. It is something that is both psychological and physiological.
What Is Leptin Resistance?
People who are overweight have a lot of body fat in their fat cells.
Because fat cells produce leptin in proportion to their size, people who are overweight also have high levels of leptin.
Given the way leptin is supposed to work, overweight people should naturally limit their food intake. In other words, their brains should know that they have plenty of energy stored.
Hmmm, not so fast.... in some cases leptin signalling may not work. While copious leptin may be present, the brain doesn't see it. This condition is known as leptin resistance.
When your brain doesn't receive the leptin signal, it erroneously thinks that your body is starving — even though it has more than enough energy stored.
This makes your brain change its behaviour in order to regain body fat. Your brain then encourages:
- Eating more: Your brain thinks that you must eat in order to prevent starvation.
- Reduced energy expenditure: In an effort to conserve energy, your brain decreases your energy levels and makes you burn fewer calories at rest.
Bit of a vicious circle hey?!
When leptin goes down, this leads to hunger, increased appetite, reduced motivation to exercise and a decreased number of calories burned at rest.
Your brain then thinks that you are hungry and initiates various physiological mechanisms to regain that lost body fat. Which are hard to just use will power to get through.
This could be a main reason why so many people yo-yo diet — losing a significant amount of weight only to gain it back shortly thereafter.
So what do we do about this?
It is hard, I am not going to lie. Managing hunger levels and getting the right balance in terms of your hormones is challenging.
- Eat protein at each meal - I know, everyone bangs on about protein. But for good reason! Protein induces prolonged ghrelin suppression and is considered to be the most satiating macronutrient.
- Eat your carbs - Yep, that's right, even when you are overweight and trying to lose fat, carbs can help to balance these hormones. How? The fibre content of carbs can help improve satiety - leading to a lower overall intake. Losing body fat is the key thing to focus on when trying to improve leptin resistance.
- Cook and cook your carbs - This increases resistant starch which takes longer to break down in your intestine, producing fat-burning butyrate and delaying hunger pangs. A great option if you are meal prepping. Rice, potatoes, oats and other grains are an excellent choice for this.
- Exercise regularly - If I am being honest, just do some form of exercise. But if you can mix it up with some fasted cardio, strength training and daily walking. This way you get the benefits from each of them.
- Eat your damn veggies - Yep, your Mum is always right. Vegetables contain high levels of soluble and insolube fibre. This helps to manage ghrelin levels making it easier to be in a calorie deficit to elicit weight loss. Do this and leptin levels go down.
I know to some of you these recommendations will seem basic. But the more I read on these complex subjects such as hormones, enzymes and physiology, the more it comes back to the basics.
Hope you enjoyed this. We have two courses on the pH Hub that will help you to manage these hormones.
Our 2 week habits on protein intake and fibre will help you to lose weight without having to count calories and macros. Just follow the guidelines!
The Hub is only £10 a month. Click below to find out more and start making progress with your nutrition today!