When most people start dieting, they slash their calories and add a large amount of exercise to their daily routine. That’s fine, but they usually cut their calories way too low. Add in the extra exercise, and all of a sudden you have an extreme calorie deficit that is working against you.
Not eating enough calories causes many metabolic changes. Your body is a smart machine and senses a large decrease in dietary energy. Your large calorie deficit might work for a few days or even weeks, but eventually your body will wake up and sound alarms that it needs to conserve energy. It doesn’t want to just waste away. It needs that energy (fat) to survive. So, what does your body do when it senses prolonged energy restriction? Not eating enough calories…
- Slows down thyroid production – Your thyroid is responsible for fat, carbohydrate, and protein metabolism among other things. Your body has the ability to slow down thyroid output in an effort to maintain energy balance .
- Decreases muscle mass – Muscle is highly calorie intensive to maintain. In a prolonged extreme calorie deficit, it is one of the first things that your body looks to get rid of. Your body needs the fat, wants the fat, and the muscle can be spared. It breaks down the muscle tissue and uses it for energy.
- Lowers testosterone levels – An important hormone for both men and women,testosterone is just one of many hormones that are affected with severe calorie restriction. Testosterone is anabolic to muscle tissue. Without it, it becomes that much harder to maintain, let alone put on muscle mass.
- Decreases leptin levels – Leptin is one of many energy regulating hormones. More importantly, it’s a “hunger” hormone that tells you whether to eat or not. High leptin levels signal that it’s OK to stop eating, while low leptin levels are a signal to eat more energy. Because of this, leptin levels decrease in calorie restricted environments .
- Decreases energy levels – There are many physical actions your body takes when you’re not eating enough calories to lose weight, but there are also some mental ones. Neurotransmitter production is limited, which can lead to a lack of motivation. It’s your body’s way of telling you to “slow down” – conserve your energy.
How Many Calories Should You Be Eating?
Your goal should be to eat as many calories as possible and still lose weight. You always want to start high and then come down with your calorie intake. It’s much easier to do this than come up in calories after your weight loss has stalled and you’ve lost all your motivation. How many calories should you eat? There is no perfect number. Each person’s metabolism is different. Calorie calculators are a good starting point, but they can’t take into account all the individualistic variables.
To do that, you need to find your calorie intake either through:
- Experimentation – I laid out a plan to determine this number in – How Many Calories Should I Eat? You might want to give it a read.
- Measure it with a device – I personally use the BodyMedia FIT Armband to determine my calorie burn. You can read more about it here. I’ve found it to be accurate within a 10% margin of error.
The problem is most people want the weight gone, and they want it gone now. Weight loss is a patience game. It takes time and consistency to make it work. Losing 2lbs per week is the most I would aim for. At this pace, it will ensure that the majority of your weight loss is coming from stored body fat instead of muscle. You will also give yourself the best chance to build muscle while you lose fat, which is what you should be striving to do. To find out what portion of your weight loss is fat and what portion is muscle, I highly recommend you pick up a $5 pair of body fat calipers to measure your body composition. It will make weight loss much easier if you can hold onto your muscle, or even put some on in the process.
So if your progress has stalled, but you think you’re eating the right foods and exercising intensely, more than likely your problem is that you’re not eating enough calories to lose weight. Eat as much as you can, get in as many nutrients as possible, and your weight loss will start moving forward again.