Trying to lose weight, start exercising, start your own business, find a more spiritual path? Then you need willpower and self-control – lots of it. But what if the amount of willpower you have is limited?

Studies in the 1990’s showed that our will power decreases through the day. We have to exert willpower more and more times through the day, but eventually run out. We only have a certain amount of willpower or self-control available.

This idea is used to explain and justify snacking in the evening:

“I’ve managed all day to restrain myself, but I’ve now run out of willpower and can’t do it anymore. That’s just how the brain works, so you can’t expect me not to snack in the evening.”

Or maybe:

“I’ve been good all week, so it’s only natural I want to pig out over the weekend. I’ve just run out of willpower, as you’d expect.”

Before I started to research my book “190 Weight Loss Hacks: What The Evidence Says” I accepted the view that the amount of willpower we have is limited. Maybe you have more than me, but however much willpower you personally have is limited. As I delved deeper, I realised that this isn’t as clear cut as that original research suggested.

Some researchers have attempted to replicate the original research without success. While there are more than 200 studies that show doing a task requiring impulse control and mental effort can lead to a drop-in self-control when switching to an unrelated task, it’s usually been tested in a laboratory setting.

More recent research in the European Journal of Personality has shown that people may be vulnerable to changes in self-control through the day, depending on whether they believe willpower is more or less limited. Limited willpower beliefs might be associated with steeper decreases in self-control across the day, which may result in less goal-consistent behaviour by the evening.

Put simply, if you believe willpower is limited, it is!

You may be thinking that you’ve never thought about willpower being limited, but you do seem to have less of it in the evening. It might be true that you have a harder time controlling what you eat when they are tired at the end of the day, but that doesn’t mean that self-control is a limited resource.

Believing that willpower and self-control are limited is likely to get in the way of controlling what you eat.

Understanding that you are likely to make poorer decisions when you are tired, is something you can address.

Associate professor Kathleen Martin Ginis, McMaster University (Canada) says:

“There are strategies to help people rejuvenate after their self-regulation is depleted. Listening to music can help; and we also found that if you make specific plans to exercise—in other words, making a commitment to go for a walk at 7 p.m. every evening—then that had a high rate of success.”

Jumana Yahya in the academic journal Frontiers in Psychology looks at whether self-control solely resides in the brain. She concludes that self-control can be triggered by outside sources. She discusses fist clenching – see Hack 04 – a calm environment and social support as “situated causes”. She writes:

“One major practical benefit of unburdening the brain of sole causal responsibility for successful self-control is that exercising this ability becomes exponentially easier. Since situated causes operate non-consciously and in a reflexive-like way, the result can be achieved without conscious effort, and not having to intentionally invest conscious effort greatly reduces – if not eliminates altogether – feelings of struggle or difficulty. Delegating the work of regulating oneself to non-conscious processes thus creates an “effortless” experience. Since the anticipation of struggle or difficulty is what causes many people who face a self-control dilemma to feel too overwhelmed to attempt being self-controlled, a less effortful experience can circumvent this consequence.”

Many of the hacks in this book are “situated causes”, taking the heavy lifting away from your brain and putting it in the environment. This allows you to create an environment that supports and triggers your efforts at self-control.