The students arrived in the laboratory in a nutrition-depleted state (they were hungry!) Each one of them was instructed to skip their previous meal before they participated in the experiment. 
Then, the psychologists unleashed their cruelty upon the participants.
They invited them into a room with the aroma of freshly baked cookies. The students sat down around a table that had two plates on it. One was the plate of the warm, delicious cookies. The other was a plate of cold, raw radishes.
Half of the students were invited to eat as many of the freshly baked cookies as they’d like. The unlucky other students were invited to…“indulge” in the radishes. The researchers then left the students alone in the room.
The radish eaters were clearly struggling with the temptation. Some stared longingly at the forbidden treats as if they hadn’t eaten in weeks. Others even picked up the cookies to smell the aroma. But, as the experiment required, they did not give in.
The students were then taken to another room to work on a geometry puzzle. They believed that the puzzle was testing their intelligence, but in reality the puzzle was impossible to solve.
The real test was to see how long the students would persevere before giving up.
This test is used by researchers around the world to measure how much willpower a person has. The more willpower they have, the longer they will spend trying to solve the impossible puzzle.
The cookie eaters worked on the puzzle for 20 minutes on average – trying to tackle it from multiple angles before finally admitting defeat. The radish eaters, though, didn’t even last half as long! After just 8 minutes, they lost their energy and gave up!
WHAT WILLPOWER REALLY IS
It was no coincidence that the radish eaters gave up so quickly. Their willpower was depleted by resisting the temptation of the cookies. So when they got to the puzzle, they had less left to use to persevere.
The cookie eaters, on the other hand, didn’t have to exert any willpower in the previous room (apparently there weren’t many radish-lovers amongst them) giving them more energy to continue the puzzle.
For almost all of history, we have believed that willpower is a virtue. Some people have it...and some people don’t. But if that were the case, why are there some days when going to the gym or resisting temptations feels effortless, and others where we cannot summon the strength to make the right decision?
The cookies and radishes experiment shows that willpower isn’t a skill at all. It's actually more like a muscle! And like other muscles in the body, your willpower gets exhausted from overuse, but it can also be strengthened with practice! 
WHAT THIS MEANS
When setting goals, many of us take the “complete overhaul” approach. We follow a new diet, we plan to exercise everyday, and become more productive all at the same time.
We can keep this up for a while, but we always end up in the same place as the radish eaters.
We deplete our willpower working on one of these goals, which leaves us with even less to take on the next one. Then we get down on ourselves. We feel like there is no way we will ever be able to reach our goals, and blame ourselves for our lack of willpower.
Then we end up right back where we started.
But this does not have to be your fate. Now that you know that willpower is like a muscle, resist the temptation to completely overhaul your life to achieve your goals. Focus on simply taking it one goal at a time.
When you focus on one goal at a time, you actually strengthen your willpower!
Think of it in terms of lifting weights. If you were to show up to the gym on day 1 and try to bench press 200lbs, you would fail miserably. Yet this is exactly what we do in life. We try to reach goals that our willpower muscles simply are not strong enough for yet.
Lifting 200lbs, is not impossible, but you need to start by lifting 50lbs first. Once you lift 50lbs, you will strengthen your muscles and be able to add a little bit more weight. Then eventually work your way up to lifting 200lbs.
This is exactly how your willpower works as well.
So do not set unrealistic - and simply unattainable - goals for yourself. First "lift 50lbs", strengthen your willpower by achieving it, then move onto the next goal. Your health, confidence and success will be much better through the process!
We tend to think of willpower as a virtue – something you either have or you don’t. The cookies and radishes experiment, however, proves that willpower is actually more like a muscle.
It gets exhausted from overuse, but can also be strengthened with the right practice. Instead of trying to completely overhaul your life – expending willpower on many things at once – focus your willpower muscle on just accomplishing one goal.
This will be much easier on your psyche, while also leading to real, sustainable, results!
- Baumeister, Roy F., Ellen Bratslavsky, Mark Muraven, and Dianne M. Tice. "Ego Depletion: Is the Active Self a Limited Resource?" Journal of Personality and Social Psychology 74.5 (1998): 1252-265
- Muraven, Mark, Roy F. Baumeister, and Dianne M. Tice. "Longitudinal Improvement of Self-Regulation Through Practice: Building Self-Control Strength Through Repeated Exercise." The Journal of Social Psychology 139.4 (1999): 446-57.