The human body is a stubborn little bugger and doesn’t like change. I’m sure we have all experienced the bodies relentless battle with reducing body fat and keeping it off. It feels like the whole world is against you. Your friends, your family and I’m almost certain the dog is egging you on to eat more pizza. Unfortunately I haven’t come with good news. Even your own body doesn’t want you to lose weight.

From an evolutionary perspective this makes sense. We are designed to survive periods of large amounts foods and periods of fasting, and our bodies make tweaks to help us be efficient at staying alive. Times have changed from hunting sabre tooth tiger and chasing gazelles across the Serengeti. It’s more McDonalds drive throughs and typing emails frantically in the office. Food availability may have changed, but our bodies protective mechanisms remain the same.

When we are attempting to lose the extra timber, we need to put ourselves in a calorie deficit. We can either do this by increasing exercise or reducing calorie intake (or a combination of both). During this time, our bodies sense the lack of food availability and begins to make changes to prevent it.

BMR Reduces

Your BMR stands for Basal Metabolic Rate and is what most people mean when they talk about metabolism. These are your coma calories. Your body requires energy to carry out thousands of bodily functions, such as breathing, heart beating and brain function. When we begin to lose weight, this will come from either body fat or lean tissue (muscle), both of which requires energy to survive. If we have less body fat or lean tissue, our BMR will be lower. So the lighter we become the less calories we require.

For more science stuff. Read this and this.

What can I do about it?

Bugger all. Being aware of the situation will help you along your weight loss journey and hopefully help you understand you need less food to maintain at the end. Also this plays an important role if you hit a plateau. The calories you required at the beginning of your fat loss period, will not be same at the end, and therefore will need to be reduced slowly to reflect your reducing BMR.

NEAT Reduces

NEAT stands for Non Exercise Activity Thermogenesis. This is the your daily activity that isn’t classed as traditional exercise, such as hoovering, walking up the stair or even fidgeting. This has been shown to reduce during periods of little food and is a mechanism to help us reduce our calorie output.

What can I do about it?

You can make a conscious effort to move more. Take the stairs, park further away from the shops/work, track your steps and get moving. NEAT makes up a huge portion of your calories burned and should not be overlooked. If you feel like sitting on your arse and do bugger all, that is what your body wants you to do. Be a stubborn arsehole, get out for a walk and show it who’s boss.

You become more efficient at exercise

The lighter you become the less weight you have to carry around. This will result in burning less calories during exercise that involves moving (such as running, cycling and even squats). Your muscles also become more efficient at producing the same energy output required.

Clever stuff!

What can you do about it?

Work harder, faster and smarter. You are not going to reach your goals by just doing the same workout each week. The weight needs to get heavier, do more set/reps or run faster and further. This is the basic principle of progressive overload and should be adhered to by everyone that trains in the gym.

Increased Hunger

There are a few hormones in the body that are responsible for hunger. One in particular is called ghrelin. This has been shown to increase during periods of low calories and also remain low for a period of time after your calories are returned to maintenance.

What can I do about it?

Hunger is a tough battle to fight. To help ease some of the hunger pains I would recommend eating a higher protein diet, higher fibre diet (loads of fruits and veggies) and staying hydrated. There will likely still be some hunger but that is to be expected.

Weight Regain

The purpose of being aware of these changes will help you during your fat loss, but more importantly they will help you when you are trying to maintain your new weight. When you bring your calories back up to your new maintenance (lower than when you first started), a lot of these bodily functions will still be trying to fight against you. With a lower BMR, decreased NEAT and increased hunger, your body will easily store any excess in calories. This is why you need to regulate and control those maintenance periods as you would during a fat loss period.


Whilst on the surface this may seem like a depressing message of failure and lost hope, the purpose of this is to educate and make you aware of your bodies mechanisms. The more you are aware of your body trying to fight back, the more you can make educated changes to your diet and training to ensue you hit your goal. If you are unsure of how to make these changes, then work with a coach (like me) to point you in the right direction.