Are low sugar diets sweet news for obesity?


Sugar Cubes by howzey

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.

Dr Justin Coleman
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One minute’s exercise — how much does it prolong your life?

One minute's execise

Time of your life
Photo by Tony Bradbury

A journal club member (Dr RB) saw a middle aged woman ask her husband to walk up a hill to their car and drive down to pick her up. She probably saved herself one minute of walking.

We know that exercise prolongs life. The question therefore is:
How much would that one minute’s walk have added to that woman’s life?

Or, more generally:
What advice could we give to sedentary adult patients about the life-prolonging effect of taking up exercise?

Continue reading

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Does zinc help with common colds? (Hint: surprisingly, yes!)

Element Zn

Zinc by AJ Cann

Does taking zinc at the first sign of a common cold actually make any difference to the duration or severity of the cold?


Population: Adults with (viral) upper resp tract infections.

Intervention: Oral zinc

Comparator: Oral placebo

Outcome: Duration of urti symptoms or symptom severity
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Do antidepressants work in people who drink too much?

Depression and alcohol

Photo: Instant Village

I am under the impression that for patients who come to see me with depression, but who also drink alcohol excessively, the addition of an antidepressant medication doesn’t seem to make much difference to their depression.

I am not thinking about specific metabolic interactions of the antidepressant and alcohol, nor primarily about ‘fixing’ their drinking problem. I just wonder whether, when faced with this scenario, the prescription of an antidepressant is likely to help the patient.

PICO Continue reading

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Fungal nails: are topicals still topical in the days of oral treatments?


A severe case of onychomycosis!


Population: People with fungal nail infections

Intervention: Oral antimycotic

Comparator: Topical antimycotic

Outcome: Resolution of fungal infection

SEARCH TERMS: Onychomycosis AND anti-fungal agent




Topical treatments for fungal infections of the skin and nails of the foot. The Cochrane Library,  Fay Crawford Sally Hollis DOI: 10.1002/14651858.CD001434.pub2

Also used:

Terbinafine in fungal infections of the nails: a meta-analysis of randomized clinical trials. British Journal of Dermatology 2002; 147: 118–121.

OUTCOME: There are 4 trials that show promise for topical anti-fungal treatment.

COMMENTS: GPs and patients are often disappointed by the results of topical treatment for onychomycosis, but these studies give some cause for hope. Sometimes it can be a preferred alternative to oral therapy. Either way, it’s not easy to cure.

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Does krill oil lower lipids or raise hype?

PICO    Population: Males/females over age of 40 y with raised lipids

Intervention: Krill oil                     Krill

Comparator: Placebo

Outcome: Lowered lipids

SEARCH TERMS: Hyperlipida(a)emia; Krill




One RCT suggested Krill oil lowered lipids. No clinical endpoints were studied

COMMENTS: Guess it might be worth the expense, although eating less fat would probably make more sense. I wonder about the Krill’s point of view–does extracting the oil lower THEIR lipids too?


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Welcome to the club — the Inala Primary Care Journal Club.

We are a group of general practitioners and primary care nurses who believe in finding evidence for how we treat our patients. We publish some research ourselves, but are particularly interested in discovering the relevant research which has already been done, and applying it to our daily medical practice.

Posts authored by Dr Justin Coleman, whose wordpress site is here. Journal club is convened by Dr Geoffrey Spurling.

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