Exercise or Diet or Both for Weight Loss

By nisus 0

There are so many options to choose from when a person decides they need to lose weight and become healthier. We know for sure that to achieve weight loss, you need to expend more energy than you consume over an extended period of time. Taking up physical activity or changing your nutrition or a combination of the two seem to be the main methods people choose to accomplish this……… But which method is more effective?

Exercise Only

We know that people who choose exercise only as their tool for weight loss will achieve results. This is especially true if you are new to the training.  In saying this however, it is unlikely that you will lose substantial amounts of weight by just training, even if it is multiple times a week. This can cause people to get discouraged, especially after the newbie results begin to slow. Hence we see a lot of people give up on their gym memberships after only a couple of months.  What people forget is the numerous health benefits that come from daily exercise. These are just a few:

  • Muscular Strength
  • Reduction in Cardiovascular Diseases
  • Heart Health
  • Immune System Health
  • Increase Brain Function
  • Healthier Aging
  • Reduce Your Risk of Some Cancers
  • Strengthen Your Bones
  • Improve Your Mental Health and Mood

When a person loses weight, they stand a much better chance of keeping it off the more physically active they are. There could be numerous reasons behind why exercise is important to prevent weight regain. One could be that physically active people tend to adhere to healthier eating practices in the long term. They seem to have the attitude of “I’m doing the training so I might as well eat better too”. Another could be that an active person is likely to have a greater level of muscle mass which can help burn more calories throughout the day. A study by Anderson et al 1999 showed that 1 year after a weight loss intervention, the most active participants continued to lose weight whereas the least active group regained a lot of the weight previously lost. This study showed the importance of keeping up physical activity even after you reach your ideal weight.

Research has also shown us that weight loss from exercise alone will lead to modest weight loss (< 2kg), but no weight loss is also possible. Substantial weight loss through exercise alone is only likely if the activity levels are well above the recommended levels of 150 minutes of moderate-intensity exercise per week. (Swift.,2014). There might be some truth in the old saying “you can’t outrun a bad diet” after all.

Diet Only

The people that choose diet as their only tool for weight loss will probably achieve very fast results if done strictly over a significant period of time. But very often these quick results are short lived.  How many people have you seen lose weight through the latest and greatest diet, only to regain it all again?! This “Crash Diet” process can look something like this and is usually repeated multiple times a year.

Step 1: The client decides they need to lose weight so they join a diet group that tell them they to need to dramatically drop calories per day to achieve weight loss.

Step 2: After a few days, they become low in energy, moody and not motivated to be physically active. But they are definitely losing weight so they keep going. Crucially though, the weight been lost is muscle mass and not fat mass. This is due to the severe calorie restriction and lack of strength training.

Step 3: Because the client has been consuming a low amount of calories for a long period of time, their body adapts, by letting go of muscle mass and burning less calories throughout the day. This means that their body now needs less calories, so in order to keep the weight off, they need to eat even less. This drop in metabolism continues for a few weeks.

Step 4: The client gives up as they find it impossible to drop calories any more and still function. Weight loss stalls. They return to their normal diet but because they lost muscle mass over the course of the crash diet, they actually gain more weight than they had when they started, even though they are eating the same amount of calories.

Step 5: The client tries to take up exercise again but realises it has become very uncomfortable due to the extra weight they are carrying. They realise that despite all the hard work they are now actually in a worse position than when they started.

The above example shows that weight loss through diet only, actually encourages the body to regain weight. Calorie restriction will definitely have more of an initial effect on weight loss compared to training alone. This is why programs out there that just focus on diet without exercise are so attractive. You will lose weight in a short period of time, but the catch is, you are likely to regain it just as fast.

Exercise and Diet

This final group, that choose to take up exercise and improve their diet, will probably be the most likely to achieve long term results. This method, from our experience, will lead to the most weight loss compared to either diet or exercise alone. A study, by John et al (2014) showed that after 6 months, a group that just focused on improving their diet were just as successful as a second group that focused on diet and exercise. But after 12 months the combined program was vastly superior. This study tells that for initial weight loss, diet will do the trick, but for long term results physical activity is required to increase or maintain the weight loss (Johns,.2014)


The sad truth is that no matter what method is used, there are only a very small percentage of people who are successful in the long term. Most people will regain the weight they lose whether that be within 5 weeks, 5 months, or 5 years. There is hope though. A study on a group of successful, long term (>1 year), weight loss individuals in America showed that they each had 5 strategies in common:

  • They consumed a low-calorie, low-fat (<25%) diet with minimal calorie variation day to day. This included weekends!! Participants reported consuming an average of 1306 (women) to 1685 (men) kcal/day.
  • They had breakfast every day.
  • They had some way of monitoring their progress e.g. Tanita Scan. They also monitored what they ate using a food diary such as MyFitnessPal.
  • They participated in regular exercise for around 1 hour per day at a moderate intensity.
  • They limited their amount of TV viewing time per day.

Basically, the above habits meant that they ate less, moved more and monitored their progress over time. They didn’t try to do anything extreme and thus they could maintain their results (Sumithran, P,.2013). We need to think of nutrition and exercise as two different tools. These tools can be effective for both weight loss and health benefits on their own. However, if you use them in combination, you can achieve far better, longer lasting results. This is the science driven approach used by Nisus and the Macro 42 System. We encourage exercise and real nutrition for long term health benefits.

21 Day Booster (Combine Diet & Exercise)

Soon Nisus will be bringing the hugely successful 21 Day Booster Program Online. Hundreds of Nisus clients have lost body fat and gained muscle mass and tone while igniting their lifestyle change with the Booster. To join the 21 Day Booster Mail List please click here


Anthony O Leary works with clients online who are looking to lose weight in a healthy and sustainable manner.

You can contact Anthony today by emailing anthony@nisusfitness.com to discuss how online coaching can help you achieve your fitness & nutrition goals


  • Andersen RE, Wadden TA, Bartlett SJ, et al. Effects of lifestyle activity vs structured aerobic exercise in obese women: A randomized trial. 1999;281:335–40
  • Johns, D.J., Hartmann-Boyce, J., Jebb, S.A., Aveyard, P. and Group, B.W.M.R., 2014. Diet or exercise interventions vs combined behavioral weight management programs: a systematic review and meta-analysis of direct comparisons. Journal of the Academy of Nutrition and Dietetics, 114(10), pp.1557-1568.
  • Sumithran, P. and Proietto, J., 2013. The defence of body weight: a physiological basis for weight regain after weight loss. Clinical Science, 124(4), pp.231-241.
  • Swift, D.L., Johannsen, N.M., Lavie, C.J., Earnest, C.P. and Church, T.S., 2014. The role of exercise and physical activity in weight loss and maintenance. Progress in cardiovascular diseases, 56(4), pp.441-447.