Skip to navigation | Skip to main content | Skip to footer

Evaluation exercise A

Read the following ’general interest’ text, which is taken from a non-academic source.

If you were to criticise this on an academic level, what weaknesses could you identify? Can you identify and note down at least three? Keep in mind the Critical Evaluation checklist (you may wish to print this out to have next to you as you read through the text below).

 

The dieters destined for failure

  1. It’s something that most dieters will have experienced – losing all those pounds only to put them all back on later.
  2. Now doctors have discovered why it is so hard to maintain weight loss. It’s all because of our hormones.
  3. A study looked at the effects of the hormone leptin, which plays a key role in regulating our metabolism and tells our body when it has had too much food.
  4. The researchers found that when we lose weight, our levels of leptin also fall, making it harder to burn off the calories and sending our weight creeping back up.
  5. The findings could explain why 85 per cent of dieters fail to keep to their target weight – and could also pave the way for new leptin-based dieting drugs.
  6. Dr Michael Rosenbaum, who led the research funded by First Great Pharmaceuticals in New York, said the key to maintaining weight loss is to keep our leptin levels high.
  7. ‘Anyone who has ever tried to lose weight knows that you never lose as much as you should for what you are eating,’ he said.
  8. ‘And even if you reach a weight you are happy with, you are never able to sustain that level of thinness.
  9. ‘Leptin fools your body into being happy with a lower weight. It won’t help you lose weight but it should help you keep weight off once you have lost it.’
  10. Dr Rosenbaum’s team looked at the effect of leptin on healthy volunteers.
  11. As the men and women lost weight, their leptin levels fell. But giving them leptin allowed them to keep to their new weight, the study, published in a US journal, found.
  12. Previous studies have shown that leptin acts as an appetite suppressant.
  13. Research last year showed that when we don’t get enough sleep, our levels of leptin fall and we feel the urge to eat more.
  14. Leptin is one of many chemicals released during sleep and it is thought that losing just an hour or two of sleep a night might be enough to cause a significant dip in levels of the hormone.
  15. The findings suggested those who regularly have too little sleep, such as night-shift workers, are at very high risk of becoming obese.

Adapted from: MacRae, F. (2005) ‘The dieters destined for failure’ Daily Mail, 2 December

 

Suggested Weaknesses

The research report would have many weaknesses if it were considered as an academic report rather than a newspaper report. They include:

  • Much essential information is not given eg paragraph 4 (How much do levels of leptin fall?); paragraph 10 (How many healthy volunteers? How were they selected? How old were they?); paragraph 11 (How much leptin were they given? How? When?).
  • No published, dated sources for this research, or previous studies, are given.
  • As the report mainly concentrates on conclusions rather than detailed evidence, methodology etc., it is difficult to judge whether the evidence is interpreted correctly.
  • The main conclusion in paragraph 2 is too general and not scientific (‘It’s all because of our hormones’).
  • The final conclusion in paragraph 15 does not follow from the evidence in paragraphs 13 and 14: (‘losing just an hour or two of sleep might be enough' does not justify the conclusion ‘are at very high risk of becoming obese’)
  • The report lacks detailed data and few statistics are given.
  • The research has been funded by a Pharmaceutical company, which might indicate some bias.
  • There is an overall lack of caution in the report. Academic writers are normally more cautious: ‘our levels of leptin fall’ could be replaced by ‘our levels of leptin tend to fall’ ‘you are never able to sustain’ could be replaced by ‘many people find it difficult to sustain’
  • The overall written style is informal and unacceptable, eg ‘It’s all because’, ‘it won’t help you’, and ‘we don’t get enough sleep’.

You may be able to think of additional criticisms.