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What Really Happens When We Decrease Calories?

Eating in a calorie deficit will generally ensure fat loss - that's a given.

However, when we disrupt homeostasis (the body’s method of keeping internal stability), we bring about both positive and negative adaptations.

This is simply how the body works. When we push one pathway long enough, the body fights back. This is why it’s crucial to NOT live in a calorie deficit.

Yes, we need to spend time in a calorie deficit to generate fat loss. But when we spend an extended amount of time in a deficit our body reacts in a negative way, and negative adaptations happen.

Firstly, let’s take a look at the positives of a calorie deficit:

1. Improved fat oxidation. When eating in a calorie deficit our body will oxidise stored body fat as energy.

2. Improved Leptin sensitivity. Leptin is a key hormone that regulates energy balance. A calorie deficit resulting in lowered body fat levels leads to improved leptin sensitivity, which is what we want. The leaner the individual is, the more optimal their sensitivity levels are.

3. Decreased inflammation. Body fat is an endocrine organ that secretes its own hormones. One in particular is called Cytokines. Cytokines are pro-inflammatory hormones (this is not good), and the more body fat we have the more they’re secreted. When we drop body fat, we have lower cytokine levels, which means we have less inflammation.

When in a calorie deficit, we want to maximise the positive adaptations but it’s very important to remember that when we push one pathway too far, that there are negative adaptations that occur. When we recognise this, we will be able to better understand how to use the positive and negative adaptations to work for us and not against us.

Some negative adaptations include:

1. Decreased metabolic rate. The longer we diet, the more our ‘calories out’ component of energy balance is compromised. This is due to metabolic rate dropping, which primarily comes from thyroid levels decreasing. The thyroid is the key regulator of our metabolic rate, and is generally down regulated by low calories, low carbohydrates and stress. The key here is to ensure that we manage our calories and understand that we don’t be in a calorie deficit for too long (more then 3 weeks), so that we always keep metabolic rate high and fat loss constant.

2. Increased hunger cravings. Leptin is the key hormone that regulates satiety. Leptin has a close relationship with Ghrelin (our hunger hormone). If leptin levels drop, this will allow for ghrelin levels to rise and increase our hunger levels. We don’t want low satiety and high hunger levels. This will most certainly have an adverse affect on our fat loss goals.

As you can see, there are negative adaptations that come from being in a calorie deficit. The key here is to make sure we manage how long we are in that deficit. We want to maximise the positive adaptations and minimise the negative adaptations.

So how is this done?

I like to use a combination of diet breaks and various cyclical nutritional strategies. This slows down the adverse effects of under-eating. Here are a few simple strategies:

Diet breaks. I use this with ALL my clients when they have finished my 4-week cycle of dieting. I was taught this from my mentor/nutrition coach, Stefan Ianev and it is also taught and used by world-renowned coach, Mark Carroll.

I increase my clients calories out of a deficit and place them at a calculated baseline calories. Baseline is neither in a deficit or surplus and therefore our body does not gain or lose weight. This is also termed as our ‘maintenance’ calories.

On a diet break I drive up mainly carbohydrates. I use a diet break for 7 days but studies have shown that it can last anywhere from 3- 14 days. The goal of restoring the negative metabolic adaptations of dieting is the focus with a diet break.

This allows us to raise our leptin and thyroid levels, which then directly raises our metabolic rate. This is crucial for promoting the ‘calories out’ component of energy balance and therefore driving up how many total calories we burn in our day.

Not living in a calorie deficit. The thought pattern of ‘eat less to lose fat and when that slows down, eat even less in the hope of more fat loss’ is very unhealthy, as well as very silly to do.

Negative metabolic adaptations begin to rise dramatically around the 4-6 weeks mark for leaner individuals (sub 15% body fat).

For people with higher body fat levels, the negative markers can hold off up to 8-12 weeks (15% body fat or higher).

This is why having a nutritional strategy and planning my clients diet breaks is so important to me and works so well. It allows for the slowing down of the fat loss process temporarily, but in turn enables a greater rate of fat loss for the days we are in a calorie deficit.

We want to ensure we not only get great results for our clients, but healthy results. Knowledge is key in every case us coaches are faced with.

We need to make sure that we understand exactly what is happening in the body so that we can tailor a plan to suit each client and get them to achieve their goal/s.

I hope you’ve enjoyed the read!

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