I’ve often wondered why checking your emails in the morning before you start work saps your energy. it appears to be a simple enough little task. But when you realise that you’re making decisions about every single email you open, you can suddenly see how decision fatigue can become a factor in your day even before you’ve started work proper.

I am most successful when I have set up habits that work. Yes, it takes a little time for any activity to become automatic, but once it’s an accepted part of your day there is very little decisionmaking to do. You just get on with the task at hand.

Going to the gym becomes easy. If you have it scheduled in and you go as a matter of course, that’s a whole lot of decisions you haven’t had to make. You want to have a protein-and-salad lunch every day? If you make it as part of your morning routine (or even the night before), it’s going to be a lot easier to eat well when the time rolls around to lunchtime.

In fact, even if it’s not all automatic, making decisions in advance can be a great help. (The automatic part is then following the plan you’ve written.) Meal planning—including having a good idea of what you’re going to do to cope with the office birthday party or the night out with friends—means you’re making considered decisions as well as saving time and effort. You can sit down and make all your decisions for the week, if that’s the way you like to roll. Then you have one piece of paper in the kitchen where all the decision making has been made. You feel so much lighter knowing that’s sorted. You know what to shop for as well. Otherwise just deciding the night before, perhaps soon after dinner or the last thing before bed, can also be successful. It becomes part of your nightly routine. Brush your teeth then sit on the side of the bed and jot down tomorrow’s must-dos and what you’re going to eat for breakfast, lunch and dinner, then slide under the covers, turn off the light and sleep soundly. Tomorrow’s only decision for all those things will be to stick to the plan.

Losing weight, as hard as it can be, is the easy part. Lots of people can do that. The real success comes in keeping the weight off so you can go through life with the body you want, the health you want and a bit of self esteem intact. And if making your decisions in advance will do the trick, then I’m all for it. Putting yourself in the driver’s seat by putting things on automatic pilot might seem a contradiction in terms, but I say viva contradictions if they work!

If you’ve studied even the simplest economics, you’ll be familiar with the Law of Diminishing Returns. It basically states that there comes a point where you actually get less benefit from increasing your investment (be it labour or some other input in the production of a commodity).

Your returns—the output per worker, perhaps—grow at first as you add each worker then reach a peak … and then diminish if you add any more workers. Obviously the smart thing to do is to find the peak and stay around that mark.

My Law of Diminishing Expenditure actually has a different slant. You start expending a lot of energy and as familiarity (habit) kicks in, you need to expend less effort. On a graph where you are plotting kilos lost, the effort expended is the vertical axis and the kilos show on the horizontal. The graph starts high and drops as you start to get more comfortable with your new diet and exercise regime over time.

To me, this works with nearly everything. You want to start going to the gym. At first it’s pretty hard. You need to find the time, organise your clothes and transport and actually get there and get sweaty. Then you need to do it again in two days’ time. The first few weeks can be pretty dreadful until it simply becomes part of your weekly schedule. No questioning about whether or not you’re going (expending more effort and adding to the decisions that have to be made that day)—it’s pretty automatic after a while, as long as you have scheduled an exact day and time in your diary.

Changing the way you eat is the same, especially if you’re following a specific programme. You have to learn how to follow the programme, perhaps buy different food and do preparation that is out of your comfort zone—considerable effort expended—but once you’ve become familiar with it all, as long as you have set in place a process that follows the guidelines, you can easily keep the momentum going.

The trick is to get out of the effort phase as quickly as possible. Work on your schedule and your habits and strengthen them to automation. Then just trust and follow the process to enjoy steady but sure results.