Why Diet Is The Key To Weight Loss … Not Exercise

OK, so the title is rather a sweeping statement, clearly exercise has a part to play in losing weight, and is particularly important when it comes to becoming or staying healthy. When it comes to achieving or maintaining what is a considered to be a healthy weight for your height however (once factoring composition such as muscle and bone of course), there is no other factor more important than diet. Diet can compensate for a below par exercise regime, but an exercise regime stands no chance of outdoing a poor diet, the old adage holds true… you can’t outrun a bad diet!


Energy balance

What do I mean by energy balance? Well it basically refers to calories in versus calories out, and getting the right amount of calories in through your diet so that it doesn’t exceed your daily requirements. It is worth remembering that energy (calorie) requirements are estimated based on a person’s weight at the time e.g. an obese person weighing in at 120kg that is comprised of mainly fat mass will supposedly need a mammoth 4200 calories per day, HOWEVER, this is what is needed to MAINTAIN their current weight and NOT what is needed to achieve a healthy weight. Similarly for protein, carbs and fat, when calculating these figures you should estimate them using their actual weight and adjust the figures by only using approx. 75% of their actual requirements to help invoke some weight loss.


Calculating ideal calorie requirements

In order to make sure the weight loss is gradual and sustainable you must not cut calories too aggressively, this can result in hormonal and metabolic shifts that make weight loss impractical and unsustainable. It is therefore best to take a person’s weight in kg and multiply it by the 35, a standard value that is used to estimate requirements which factors in moderate activity levels too. For example a 120kg male would do the following:

120 x 35 = 4200 calories

Now that you have the amount of calories needed to MAINTAIN weight, you then need to adjust this to invoke some weight loss. To keep the weight loss achievable and sustainable aim for 75% of their requirements to maintain weight:

4200 x 0.75 = 3150 calories

This calorie intake will put this person on the right lines, monitor weight loss every couple of weeks and finally after 1 month run their weight through the first calculation above e.g. 115kg x 35 = 4025 calories and factor in 75% calculation once again e.g. 4025 x 0.75 = 3018 calories (feel free to round these calories down to 4000, this is an estimation after all).


Focus on whatever feels most natural

In my experience of working with obese individuals, it isn’t always easy to get the client to apply nutrition AND fitness advice at the same time. If you notice that you (or the person in question) has an affinity to exercise for example, then push that to hilt because if they feel that they are succeeding in one area of the weight loss journey (even if exercise is the less significant of the two factors), then they tend to feel more confident and encouraged to apply the other variable i.e. nutrition. Little successes breed bigger successes, the feeling of achievement that a person may get from succeeding at exercise or nutrition is often enough to make them stick at it, sometimes it’s best not to push too much too soon.

Although I recognise that exercise is a very useful tool to encourage weight loss, too many people place too much emphasis on it when trying to lose weight, when in actual fact they would glean much better results by cleaning up their diet. At 120kg for example, it is not uncommon for these people to struggle with physical activity due to the strain 120kg places on their joints and cardiorespiratory system (heart and lungs), so in order to start the weight loss off it is essential that diet is amended accordingly. Do not place all of your emphasis on exercise when losing weight thinking that the 30min walk or 40min run you did negates the 3 doughnuts you are about to devour… it doesn’t work like this. Earn the right to lose the weight by getting the diet right, ensuring it is calorie controlled as per your requirements (use the calculations above), and then incorporating a tailored and structured training regime to cumulatively improve your weight loss potential.

There are supplements that are designed to kick start a fat loss regime, they act on metabolic rate meaning you burn more calories when at rest. So combine a weight loss supplement with a balanced diet and consistent training regime, and you will be well on your way.

About the Author

Job Role Qualified Dietitian and Sports Nutritionist Qualifications BSc (Hons) Sports Science | BSc (Hons) Dietetics Tom has always participated in sport both recreationally and competitively which led to an unquenchable thirst for information on anything health, nutrition and fitness. After leaving school Tom went on to play for a football academy during which time he studied Sport and Exercise Science. From here he went on to study a BSc (Hons) Sport Science at UEA followed by his second BSc (Hons) degree, this time at the University of Hertfordshire studying Dietetics. Tom has worked in the fitness, educational and clinical nutrition industry starting out at David Lloyd Health and Leisure Clubs. He then went on to work as a Dietitian (RD) in the NHS, during which time he conducted clinics for healthy eating, weight loss and weight gain, as well as specialised consultations on Diabetes, IBS and Coeliac disease to name a few. He has vast amounts of experience at devising diet plans and supplement regimens, as well as working in the community with schools and competitive athletes. As Head Nutritionist and Supplement expert at Discount Supplements Tom is here to provide current and evidence based health and nutrition information to help you reach your health and fitness goals!


  • Craig
    May 12, 2015 Craig

    While it's great to see an article emphasising diet over exercise, why doesn't this mention the use of body fat percentage when calculating calorie requirements? The calorie intakes needed to maintain for someone weighing 100kg with 10% fat vs someone who is 100kg and 35% fat are surely hugely different? Using one of the <a href="http://www.calculatorpro.com/calculator/katch-mcardle-bmr-calculator/"online Katch McCardle calculators, the latter scenario says 1,774 calories per day, with the former scenario needing 2,314.

    Quite a difference

    • Tom

      Very valid point Craig! Yes % fat will influence this, good call. It does mention the importance of factoring body composition doesn't it?

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