'For me it's about not feeling like I'm on a diet': a thematic analysis of women's experiences of an intermittent energy restricted diet to reduce breast cancer risk

BACKGROUND

Weight-loss programmes requiring intermittent energy restriction offer an alternative to continuous energy restriction programmes that typically have low adherence. We reported greater weight loss, better adherence and spontaneous reduced energy intake on healthy eating days with intermittent as opposed to continuous energy restriction. The present study aims to explore why intermittent energy restriction diets exert these positive effects.

METHODS

Semi-structured interviews were carried out with 13 women aged 39-62 years, who followed a 4-month intermittent energy restriction (2 days of low energy/low carbohydrate, 5 days of healthy eating). Nine of the 13 women successfully lost >5% of their total body weight. Data were analysed using thematic analysis.

RESULTS

The intermittent regimen redefined the meaning of dieting and normal eating. Women reconceptualised dieting as only two low energy days per week, even though this often differed from their pre-diet eating patterns. Women reported that they could adhere more closely to the rules of the intermittent diet compared to previously attempted continuous diets. They found that the intermittent diet was less cognitively demanding because the restrictive and clear rules of the intermittent diet were easier to understand and easier to follow than with continuous dieting.

CONCLUSIONS

Many participants found intermittent dieting preferable to previous experiences of continuous dieting. The findings provide some insight into the ways in which intermittent dieting is successful, and why it could be considered a viable alternative to continuous energy restriction for weight loss.

P3-09-02: Intermittent Dietary Carbohydrate Restriction Enables Weight Loss and Reduces Breast Cancer Risk Biomarkers

Background: Energy restriction is a potential strategy for breast cancer prevention but is difficult to achieve and maintain. We found that intermittent energy restriction (2 days strict dieting week) is comparable to the standard approach of moderate daily restriction for weight loss and marginally better for improving insulin sensitivity, but no easier to follow1. In this follow on study we wished to test whether 2 novel intermittent low carbohydrate/low energy diets were feasible and easier to follow than a standard daily energy restriction. Design: Randomised comparison of 3 dietary types over 4 months in 115 overweight or obese (mean body mass index 31.0 [±5.3 SD] kg/m2) women at increased risk of breast cancer (lifetime risk > 1 in 6).

Diets:

1. A restricted low carbohydrate diet (RLCD): 650 kcal and <50g carbohydrate / day for 2 days per week

2. Ad lib low carbohydrate diet (ALCD): <50g / day for 2 days per week with other food types (e.g. protein) ad lib

3. A standard daily restricted Mediterranean diet (DRMD): ∼ 1500kcal/day for 7 days per week

Methods: Weight, anthropometrics, blood markers for breast cancer; insulin resistance, oxidative stress markers, leptin, adiponectin, lipids, inflammatory markers IGF-1 were assessed at baseline, 1, 3 and 4 months.

Results: 88/114 completed the study (77%, drop outs 6 RLCD, 8 ALCD 12 DRMD). Last observation carried forward analyses show both intermittent low carbohydrate diets were superior to standard daily restriction for reducing weight and body fat: mean (95% confidence interval [CI]) change in body fat for RLCD was −4.3 (−5.6 to −3.0) kg, for ALCD −4.1 (−5.2 to −3.1) kg vs. −2.4 (−3.4 to −1.2) kg for DRMD (P value for difference between groups = 0.02). The intermittent groups had greater improvement in insulin resistance: mean (95% CI) change for RLCD was −22 (−35 to −11) %, ALCD −14 (−27 to −5%) % vs. −4 (−16 to 9) % for DRMD (P = 0.02). Other biomarkers are being assayed currently.

Conclusion: Greater weight loss, fewer drop outs and greater reductions in insulin resistance with the novel intermittent low carbohydrate diets indicate that these are alternative approaches for energy restriction for potentially reducing risk of breast cancer and other diseases.

Reference:

1Harvie MN, Pegington M, Mattson MP, Frystyk J, Dillon B, Evans G et al. The effects of intermittent or continuous energy restriction on weight loss and metabolic disease risk markers: a randomized trial in young overweight women. Int.J Obes (Lond) 35; 714–27, 2011. This study is funded by the Genesis Breast Cancer Prevention Appeal: www.genesisuk.org

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-09-02.

P4-12-01: The Breast-Activity and Healthy Eating after Diagnosis (B-AHEAD) Study – A Randomised Comparison of Weight Control Programmes during Adjuvant Treatment

Background: Excess weight at diagnosis and weight gain during treatment are linked to increased mortality from breast cancer. Since 60% of breast cancer patients are overweight at diagnosis and 75% gain weight during treatment, weight control should improve outcome but the optimal intervention is unknown.

Aim: To compare 3 programmes for weight control after surgery for primary breast cancer.

Methods: We have recruited a randomised trial of 2 diet and exercise weight control interventions (1. a community based supervised group programme, 2. a mail and phone programme) compared to standard written advice (control). We are comparing the relative effects of the 3 programmes on body weight and composition (by dual energy x-ray absorptiometry), cardiovascular risk parameters (lipids, blood pressure), a marker of breast cancer prognosis (insulin resistance), fitness and quality of life over the first year after diagnosis.

In total 409 women have been randomised (45% of eligible women) and 21 women have left the trial (5.1%), 357 have completed the 6 month assessments, all are due to complete the trial in December 2011.

Results: