Diet vs. exercise: A few facts to help you decide which to invest in

diet or exercise

Over 68% of men and 58% of women are obese or overweight in the UK and weight loss is a goal of the masses. In general, there are three camps in which weight loss advice falls. A few facts from each are outlined below:

With diet alone

  • A recent study showed that subjects lost on average 4 kg but after two years could only sustain a 2 kg total loss.
  • Diet alone will not improve metabolic rate of cardiovascular fitness, which are key components of health.
  • A deficit of approximately 500 kcal per day is required to initiate any weight loss.

…With exercise alone

  • 150 to 250 minutes per week of moderate physical activity alone (brisk walking etc.) is required to prevent weight gain.
  • 225 to 450 minutes per week of physical activity is required to bring about significant weight loss (~5 to 7.5 kg).
  • Currently only 61% of the population are achieving the government recommended guidelines of 150 minutes per week of physical activity.
  • 26% of the population are performing less than 30 minutes per week.
  • A 2007 study showed, exercise alone reduced body mass by 2 kg in 6 months but the weight was regained within 12 months.

…Exercise and diet combined (as recommended by us)

  • In the same 2007 study mentioned above, combining a balanced diet and exercise led to a sustained 5 to 6 kg weight loss. The weight loss remained for four years following intervention. Some subjects in the 2007 study lost up to 8 to 9 kg.
  • Nutrition effectively fuels your exercise and physical activity through the day, while exercise complements the use of fat and carbohydrates consumed within your diet. It is a necessary and symbiotic relationship.

So, you guessed it, the best ROI comes from both, invested in in a controlled manner, over a sustained period time. No short cuts.


  • Donnelly et al. Med Sci Sport Exerc, 41(2): 459-471, 2009.
  • Franz et al (2007), J Am Diet Assoc.