Doctors, like other non-doctor humans, read about new diets all the time. Many can be safely dismissed as fads, but some warrant closer attention. We wondered if sugar-elimination diets actually result in weight loss. Like so many things in life, it seems like they should work – but do they?
Population: Obese adults on a Western diet
Intervention: Low sugar diet [We felt ‘very-low or no-sugar’ was impractical]
Comparator: Normal diet
Outcome: Weight change
SEARCH TERMS: low sugar diet AND obesity
DATABASE USED: Pubmed clinical queries, specifying the limiters ‘therapy’ and ‘narrow’
HITS: 50 systematic reviews
REFERENCES: Hit number 12 was the most relevant, from BMJ 2012. Dietary sugars and body weight: systematic review and meta-analyses of randomised controlled trials and cohort studies.
OUTCOME: Low sugar diets result in an average of 0.8kg weight loss (95%CI: 0.4 – 1.2kg). The studies averaged five weeks of dieting. Studies which replaced sugar calories with other calories (e.g. complex carbohydrates) showed no weight loss.
COMMENTS: I was happy to discover that, this time, the ‘makes sense’ outcome did apply. Losing 800 grams is not a lot, but of course is only an average. Across various RCTs and cohorts, the effect was consistent and showed a dose-response relationship, providing evidence that the stricter you are with the low sugars, the more weight you can expect to lose.
We suggest people steer clear of fad diets (anything containing the word ‘miracle’ or ‘cure’, for starters), but reducing sugar as part of a well-rounded diet seems to predictably result in weight loss.