When setting the goal of losing weight, many believe it can only be achieved by committing to intense exercise programs and adopting a restrictive diet. The truth is, we often make it much more complicated and difficult than losing weight needs to be. 

Energy Balance

Before we talk about the role exercise plays in weight loss, it’s important that you understand the core principles of weight and energy balance. Essentially, whether we lose, gain or maintain weight is a result of the calories we consume in relation to how much energy we expend, or burn.

Each day, our bodies use a specific amount of energy, our Basal Metabolic Rate, for automatic and essential body functions like breathing and digestion. By combining our Basal Metabolic Rate with any exercise or physical activity, we get our Total Daily Energy Expenditure. That number is expressed in calories, which is simply a measure of energy.

If the total calories in the food we eat in a given day is less than the calories we burn that day, then we experience a calorie deficit. Maintaining a consistent calorie deficit over time results in weight loss. That’s why eating less and burning more calories with exercise leads to losing weight. 

That exact principle can be applied to maintaining and gaining weight. If we consume approximately the same amount of calories to the total calories we burn in a day, then we maintain weight. If we regularly eat more calories than we burn, we gain weight. It’s that simple.


Exercise Vs. Diet

You may have been led to think that exercise is essential to losing weight, but the truth is, diet is the biggest influencer in whether we lose, maintain or gain weight. The healthiest and most sustainable way to lose weight is by eating nutrient-dense, low-calorie foods that nourish the body whilst maintaining a calorie deficit. 

My point isn’t to discredit exercise entirely. Exercise is scientifically proven to prevent and improve a range of physical and mental health concerns both immediately and long-term. However, it’s not nearly as crucial as diet in regard to losing weight. Increasing physical activity simply increases the likelihood of having a calorie deficit or at least lowering a calorie surplus.


The Difference Between Losing and Gaining

For example, consider Angela and Diana. The two women eat healthy and burn the same amount of calories during F45 sessions, which they do together on the same day and time. However, Angela is gaining weight whilst Diana is losing weight.

The only thing different is the amount they eat. Angela often eats 1-2 more snacks than Diana does per day. Whilst it may seem like a minor difference, that calorie surplus adds up over time and leads to weight gain. 

I use that example to demonstrate just how important diet is in weight loss. If energy consumption is too high, you don’t need to drastically increase exercise to lose weight. Rather than relying on exercise, the key is getting nutrition right.

To calculate your BMR & total daily energy expenditure (TDEE) check out Eimele’s TDEE calculator.


‘Bad’ and ‘Good’ Days

It’s important to note that our bodies and our weight are not defined by one day. Our weight is more of a reflection of the ongoing average over time of the calories we consume versus the calories we burn. That’s why it’s key that you don’t let one ‘bad’ day completely derail your weight loss goal. It’s also why you need to be patient and not get disappointed when you don’t see instant results after a few ‘good’ days.

Summary & take home tips:

  • Weight loss, maintenance or gain is the net result of energy balance (energy in versus out) over time.
  • If weight loss is your goal, foods low in calories per bite yet rich in fibre and plant protein should be the focus of your diet.
  • Don’t beat yourself up over one day!  Remember energy balance over time is what leads to changes in body composition. If you have a bad day, think about making small improvements over the following 6 days to get your week back on track.
  • Exercise is a useful tool to help increase your calorie deficit, and has other health benefits beyond body composition, however, you can’t out exercise a poor diet.