Diet or Exercise: Which is More Important for Weight Loss

diet or exercise for weight loss

This topic is very close to my heart and I am writing this as a guide to help other people trying to lose weight. Like many of you - over the years - I found myself gaining weight steadily. In fact - not that long ago - I was more than 30 kilograms overweight.

Like thousands of others, I tried it all to lose weight: 'eat less, exercise more', but it just did not work. Exercising was impractical for me, I hated it and led a relatively sedentary lifestyle.

I tried counting calories and cutting carbs and fat or depriving myself of my favourite foods. It gave me results temporarily but I regained the little weight I had lost in no time. I knew there had to be another way. I believed that we were all being misled by much of the advice in the popular magazines and TV programs.

Why do we gain weight?

To solve the riddle of diet versus exercise: which is better, we need to go to the basics: that of why we gain weight.

The fat tissue or adipose tissue is the main area where the human body stores fat. It is also the calorie buffer for the human body and without it we would starve to death. Changes in the amount of fat we carry vary based on the calories we put in versus the calories we burn through metabolism and exercise.

So, in order to lose fat, we must have the number of calories leaving the body exceed the number of calories entering it. Short of liposuction - there is no way around this mathematic equation. Sounds easy but implementing it is not so straightforward and simply 'eat less, move more' guidance does not provide long term results for most people.

Think about it...

We are told over and over that weight gain is a simple matter of consuming more calories than the number of calories burnt. We are advised that weight loss will occur mathematically and predictably if we cut back on the calories that go inside us through food and burn more calories going out through heavy exercise.

It all looks fine on paper, makes sense even, but for most people out there, it is an impractical solution to losing weight. On the days I exercised, I felt I deserved a treat and so I would end up eating more. Also, the days when I starved myself, I felt irritable and moody. It just was not the solution one could count on for permanent weight loss sustenance.

Could diet alone be sufficient?

I did some math to test this theory further. I realised that if I skip on two tablespoons of extra virgin olive oil which I drizzle on my salad, I could cut back on 238 calories. If, at this rate, I continued maintaining my relatively sedentary lifestyle, I could predictably lose about 0.5 kilos of weight every 2 weeks which measured up to 1 kilogram of weight loss per month making me 12 kilos lighter at the end of the year. It all sounded easy, and predictably, but, and as shown by nationwide experience, it just did not work.

Obesity: An epidemic

According to a recent article, obesity rates in Australia are climbing faster than ever. Australian obesity statistics are now believed to be at par with American stats. Nearly 75 - 80% of middle aged men in our country are now medically overweight.

To fight this epidemic, there is an unfortunately wide circulation of a variety of nutritionally imbalanced and unhealthy diets, weight loss and exercise regimes. In the United States, where nearly 64% of the population is overweight, there is prevalence of a wide range of fad diets including the following:

Cabbage soup diet - cabbage soup diet belongs to the category of "eat-only-one-type-of-food" diet. Termed as the magic formula to “burn fat”, this diet became extremely popular in the 1980s. It consists of eating cabbage soup and nothing else for 7 days to radically aid weight loss and “burn” fat.

The diet came under heavy criticism after it was revealed that the weight lost at the end of 7 days was just water loss and not fat loss. Naturally such an elimination diet just cannot yield permanent results. Now experts are saying that eating large quantities of only one type of food can give rise to bloating and intestinal gas and lead to malnutrition.

The next to hit the scenes were low carb diets, examples of which include the famous Paleo and Ketogenic diets. Both Paleo and Ketogenic are low in carbohydrates, rich in proteins and moderately high in good fats. People took to these diets because they were not calorie restrictive and one actually got to eat a wide range of low carb foods.

Many people claimed success with these diets. Even bodybuilders, serious athletes and celebrities are still known to follow these diets even today.

In a recent study, rather a meta-study, researchers studied these different low carb diets on 59 individuals to see which one reigned supreme. The results: None! This is because significant weight loss was observed with any low-carb or low fat diet. Also the individual differences in weight loss between diets were very little. This concluded that the best diet is the one that is practical and to which a patient can comfortably adhere to in order to lose weight.

But what do doctors say about low carb diets?

Carbohydrates are the main sources of energy for the human body. Excess carbs are naturally stored as fat and therefore, limiting carbs is the main premise of all low carb diets.

However, there is a big problem which is overlooked by proponents of these diets: our body actually needs carbohydrates to oxidize fat. When you limit carbs, your body gives rise to ketones. Ketones are toxic to human bodies when produced in excess so one must drink plenty of water to excrete them out. If you fail to do so, your kidneys are unable to remove ketones, which then accumulate in the blood leading to ketosis.

Ketosis causes the body to go into the same state as it does during extreme fasting or starvation. Starvation can be extremely dangerous if continued for long periods of time. Ketones also suppress the body’s natural appetite – which is a way of conserving energy.

To further support this, and as per report by the Food And Nutrition Board of National Research Council in United States, adults need at least 500 calories from carbohydrate sources. So paleo, ketogenic and other low carb diets like grapefruit having less than 500 calories from carbs, might result in weight loss but they also result in lean muscle loss.

So is heavy exercise the answer to weight loss?

We are constantly being told that heavy exercise is the only way to lose weight and that it is also the panacea to many of the life’s ills. TV shows like Biggest Loser reinforce these myths. But that kind of exercise is often impractical, as it was in my case.

Not only do most people not have time to exercise for hours every day, there is no evidence that doing so will actually help one see expected  long-term results.

According to British doctor and TV Journalist, Dr. Michael Mosley, “exercise alone cannot promise fast weight loss”. He observed that many gym goers actually went into the rewards mentality - they felt they deserved a reward because they had exercised heavily which led to weight gain. Only an average of 20% of gym goers actually ends up losing weight.

So yes, exercise is a good way to keep off the weight but it is not the best way to lose weight. Even a study on Marathon runners illustrated this point: a Harvard study on 64 female charity runners showed that none of them lost weight over the course of 3 months-4-day running program. In fact, at the end of the program, most women were heavier.

Time for some more math:

Half a kilogram of body weight approximately equals to 3500 calories. Since you are looking to burn fat calories, you need to put in even more efforts. So, you would need to create a weekly caloric deficit of 3500 calories and - for example - run an average of 60 kilometres every week in order to burn just ½ kilogram of weight! That is just too much work for a lousy half kilogram of weight!

My weight loss journey

There is no clear winner in the diet vs. exercise debate. It is a combination of both that will give you the results you are looking for. Both these factors can help shift the balance towards energy deficit and that is what is needed to see results.

It remains however, that you cannot lose tons of weight by heavy exercise nor through diet alone. All your good efforts in the gym will be blasted away if you get hungry and have a carbohydrate dense piece of sweet bread after the work out.

It is also impossible if you are as busy as I am and used to dislike exercise like I did.

Throughout my research I realised one thing: it was easier losing weight on paper than in reality. Yes, it all boils down to an energy equation in which you cut kilojoules going in and increase the kilojoules going out.

So, the clear winner is a combination of moderate exercise with healthy and clean eating with focus on real foods. Here is what I did:

  • I started off by removing all unhealthy or not nutritious food from my pantry - breads, pastas, ice cream and fruit juices.
  • I calculated my Basal Metabolic Rate.  BMR is the minimum number of calories your body needs at rest to fuel its metabolic activity, for example to maintain functions such as heart beat, breathing and temperature. BMR for an individual and is based on age, height and weight and also your gender.

    Comparing calories consumed in my food with my BMR gave me the exact calories I need to burn or eat less of, to reach my goal.

For Women: the Basal Metabolic Rate is:

BMR = 10 x weight (kg) + 6.25 x height (cm) – 5 x age (years) – 161

For Men: the Basal Metabolic rate is:

BMR = 10 x weight (kg) + 6.25 x height (cm) – 5 x age (years) + 5

Now to find your total daily calorie needs you need to adjust your BMR for your activity level

If you are sedentary: BMR x 1.1

If you participate in light exercise 2-3 times a week: BMRx1.275

If you are moderate active (playing sports 3-5 times a week): BMRx1.35

If you are heavy exerciser- (hard sports or gym 6-7 times weekly): BMRx1.525

If you exercise very heavily-(physical jobs, training twice a day for 7 days): BMRx1.7

  • From this equation, I determined for my relatively sedentary lifestyle my Basal Metabolic rate was about 1500 calories. My daily calorie intake had to be lowered so I put myself on a 1200 calorie per day diet.
  • I focused on lean meats/fish and fresh fruit and vegetables. I ate more organic. I drank more water.
  • I put emphasis on whole grains like quinoa and chia, ate less rice, bread or potatoes and drank protein shakes to keep me full and satisfied.
  • I started to exercise – just not too much – I took up activities that I really enjoyed - like swimming. I tried to make it to the gym once or twice a week.
  • What I certainly did was stay away from fruit juices and calorie-rich deserts and foods because I knew those were the reason I put on weight in the first place. I trained very hard in the gym and I certainly didn't want to waste my efforts.

The result: I lost 8 kilos and also managed to keep them off. So you really need not work too hard in the gym. Nor do you need to starve your body with fad diets.

In conclusion

Some might tell you that nutrition or diet is the most important factor for weight loss-others will ask you to slog it out at a gym. Interestingly, and through my own experience, it is not about whether diet or exercise plays a more important role in helping you lose weight but rather what you believe to be true.

If you think it is exercise, it might lead you to higher calorie consumption. If you think it is diet alone, then you might not exercise much thereby being unaware of the activity levels needed to burn those calories.

As the prevalence of obesity and weight related disorders increases, we have to urgently enhance our understanding of diet and exercise and how they impact short-term and long- term weight loss as well as other health outcomes.

Low carb and low fat diets come with their shares of advantages and disadvantages so a single diet recommendation is unrealistic based on the variable responses among individuals to the same diet.

From a public health perspective though, some exercise is better than no exercise. Strength training is specifically recommended. It is good for overall lean mass and tones and shapes your body. So go for a pre-evaluation plan and evaluate any program you decide upon thoroughly through outcome measures before taking them up.

The program you will choose must also include a permanent maintenance plan in order to be successful. Good luck! You really CAN lose weight!

Barbara Komorek

Barbara is the founder and owner of www.leanhealthyandwise.com. She is a former research scientist with a serious passion for health. She enjoys writing about nutrition, wellness and lifestyle and empowering people to take control of their health.