You're dedicated and disciplined. Awesome. Now it's time to be smart too. Don't make this common fat-loss mistake.
One of the Worst Diet Mistakes
Ready to get lean? Believe it or not, one of the worst mistakes you can make is to eat too FEW calories early into your cutting plan.
First let's differentiate between a fat loss blitz and a more traditional approach. The former refers to using extreme measures to lose as much fat/weight as possible in a very short period of time. Normally two to four weeks.
If those measures are sustained for longer, bad things happen: libido drops, hormones levels get messed up, and metabolic adaptations occur that make fat regain likely. Your physical and mental performance will drop significantly too.
This strategy is for extreme situations only. For example, it could be used by an extremely obese person who has to drop as much weight as possible in a few weeks to be allowed to get a surgery more safely. It could also be used by physique competitors at the tail-end of their prep. They might need extreme measures to drop down to the level of body fat that's required for competition.
What YOU Should Do
Most people should use a more gradual approach: spending 8-16 weeks to drop fat without negatively affecting health or well-being.
For the gradual fat loss approach, one of the worst mistakes is to start out too aggressively by cutting calories too much. There is such a thing as metabolic adaptation: after a period on a certain caloric intake, your body will adapt and initiate "countermeasures" that'll make it harder to keep losing fat.
For example, leptin levels will decrease which will increase your hunger and cravings – your body is trying to force you to eat more calorie-dense foods. Lowering leptin will also increase depression symptoms – one of the reasons people feel bad when they diet too hard for too long. Those depression symptoms might lead to "hedonic binge eating" to get a pleasure response and pull us out of that depression state. Decreasing leptin might also lead to a lowered metabolic rate.
The body will also increase ghrelin levels, which will dramatically increase hunger. Again, a strategy used by your body to trick you into eating more to get out of the perceived excessive deficit.
A Cortisol Conundrum
As a refresher, two of the main functions of cortisol are:
- Mobilizing stored energy when you need it
- Increasing blood sugar levels when they're too low
The bigger the caloric deficit (especially if that deficit comes with super-low carbs), the more energy you need to mobilize, and the higher cortisol will be.
High cortisol is bad for muscle mass. So right off the bat it's something you should try to avoid. But chronic cortisol elevation can also affect fat loss. When released at the right time, cortisol is actually a fat loss hormone, but if it becomes chronically elevated it can hurt your fat loss efforts.
Why? Because chronically elevated cortisol levels will lead to a decrease in T3 (a thyroid hormone) levels. And T3 levels play a huge role in how fast your metabolic rate is.
We have two main thyroid hormones: T4 and T3. T3 is the one that has a huge impact on metabolic rate. T4 not so much. The body doesn't produce a lot of T3. It starts by producing T4 and then converts what it feels is "safe and needed" into T3. But chronically elevated cortisol will inhibit the conversion of T4 into T3.
So when cortisol is elevated acutely, then comes back down, it's good for fat loss. But if it's chronically elevated (like in period of excessive caloric restriction) it can decrease your metabolic rate, making it harder to establish a deficit and lose fat.
On top of that, low T3 is associated with low energy. So if it's high for too long, you'll not only have a lowered metabolic rate, but you'll also feel lazy and move a lot less throughout the day, which means you'll expend less energy.
If you're too hasty with caloric restriction, you'll eventually adapt to that level and fat loss will slow down or even stop. And then what are your options? Eat even less? Not smart if you're already at the low end of your needs. Train more? Sure, but your body will adapt there too, and you'll quickly be stuck without a way to keep progressing.
And remember, you'll feel like crap, have cravings, experience depressive symptoms, and feel drained.
The Better Approach
Start with the smallest caloric deficit that'll allow you to lose fat at an acceptable rate (around 2-3 pounds per week for most).
As fat loss slows, you'll be able to gradually (key word) lower caloric intake to continue progressing.