Given the massive adverse effects of obesity and overweight status, now of pandemic proportions and affecting a wide spectrum of cardiovasuclar, diabetic, cancer, and neurocognitive (including cognitive impairment, dementia and Alzheimer's) health, it's a global imperative to maintain optimal weight AND to consume an optimal diet, and if overweight or obese, to engage in a weight reduction program to normalize weight and body mass.
The only effective method to keep off excess weight is through committed weight management and obesity prevention, involving physical activity, balanced with a healthy diet, and studies show that combined dietary and exercise components lead to the greatest improvement in physical performance measures and quality of life, and this combination mitigates reductions in muscle and bone mass observed in diet-only study arms. Here's what the best science tells us:
The caloric level of one's diet is first and foremost in any weight loss intervention, and in fact the data suggests that a properly calorically restricted diet typically yields clinically meaningful weight loss regardless of the content of the macronutrients contained, although - beyond just weight loss - diets rich in low energy density and low glycemic foods (fruits, vegetables, and high-fiber content, soups, etc.), reduce caloric intake while also promoting satiety, and this is superior to a fat and portion restricted diet.
The core principle of caloric restriction is that diets reducing caloric intake to approximately 1,200 to 1,500 calories in women, and 1,500 to 1,800 calories in men, will produce appreciable, regardless of their macronutrient composition, given the established fact that these caloric levels engender a caloric deficit for most overweight and obese adults. Note that NIH (National Institutes of Health) has recommended lower calorie diets of 1,000 to 1200 calories for women, and 1,200 to 1,600 calories per day for men, but data suggests that this may be associated with rather low adherence.
However, the principle remains the same in both scenarios: a deficit of approximately 500 to 1,000 calories per day will be created, which results in gradually progressive weight loss of one to two pounds per week.
It's critical to avoid inactivity, and some - ANY - physical activity is better than none. But for the most substantial health benefits, adults should do at least:
- 150 minutes (2 hours and 30 minutes) a week of moderate-intensity (5 days of 30 minutes each, or each of seven days at ~20 minutes daily), OR
- 75 minutes (1 hour and 15 minutes) a week of vigorous-intensity aerobic physical activity, OR (best):
- an equivalent combination of at least moderate intensity aerobic activity coupled with strength/resistance (weights) training which involves all the major muscle groups, are recommended for two or more days per week.
The Anticancer benefit: This last point bears fleshing out, namely that the combination of Caloric Restriction + (Physical) Exercise intervention, CREX for short, is especially critical, for general health, for weight control, and for cancer risk reduction. A randomized controlled trial (RCT) from Anne McTiernan and colleagues at the Fred Hutchinson Cancer Research Center showed an amazing estradiol reduction of 20.3% and a free estradiol reduction of 26%, with a 15.6% decrease in free testosterone, along with significant reductions in insulin, C-reactive protein CRP), and leptin, and favorably increased adiponectin from this combination intervention.
And as the investigators correctly observed, based on best evidence to date, just the decrease in mean estradiol alone from such a Caloric Restriction + (Physical) Exercise intervention could represent at least a 50% or greater reduction in breast cancer risk, solely from the caloric restriction / weight loss part of the intervention. And we know from the NEW (Nutrition and Exercise for Women) trial results that patients randomly assigned to exercise alone experienced smaller but significant changes in estrogen, testosterone, and leptin levels, and the combination of these trial suggests that modest weight loss is able to effect the same change in biomarkers as more significant weight loss, if - and only if - the modest weight loss was combined with exercise.
In addition, given the pathogenic role of insulin molecular pathways in one of our more challenging forms of breast cancer, namely triple negative breast cancer (TNBC), these shows that these findings are not constrained to only endocrine positive BC, but benefit all populations: healthy, obese/overweight, and breast cancer populations alike.
Commercial Weight Loss Programs
Surprisingly, these programs are underutilized although studies, both medical and consumer (like from Consumer Reports), find several of them consistently effective and affordable. In a recent meta-analysis and systematic review [Gudzune et al. Ann Intern Med 2015] of 45 studies, 39 being RCTs, it was found that at the 12 month checkpoint, Weight Watchers participants achieved at least 2.6% greater weight loss than those assigned to control/education, while Jenny Craig resulted in at least 4.9% greater weight loss at the same checkpoint (Nutrisystem resulted in at least 3.8% greater weight loss than control/education and counseling, but note that was at 3 months).
So the takeaway advice is that people should consider programs like Weight Watchers or Jenny Craig if a self-directed regimen isn't successful or feasible, and I note that Weight Watchers even has a easy-to-comply-with online plan (with expert chat and video support) called OnlinePlus: https://www.weightwatchers.com/us/plans/onlineplus that may be appealing as physical travel and direct meetings are not always viable, and that can be combined with some meetings in their Meetings + OnlinePlus plan: https://www.weightwatchers.com/us/plans/meetings
Besides it's well-attested cardiovascular benefits, the Mediterranean diet resulted in greater weight loss than a low-fat diet at ?12 months, with similar weight loss as other comparator diets [Mancini et al. Am J Med 2016]. And it is now known that the likely most critical component of that diet is olive oil, so one should substitute it for other fats (aim at 2 - 4 tablespoons daily). In addition, research conducted at the Miriam Hospital and Brown University in Providence (RI) found that for breast cancer survivors, an olive oil-enriched diet produced a greater weight loss than a lower-fat diet [Flynn & Reinert, J Women's Health 2010].
Other "Adjunct" Interventions for Weight Loss
Results from meta-analysis of eligible trials revealed that subjects who received l-carnitine (dosing between 500 mg to 1,000 mg three times daily) lost significantly more weight and showed a decrease in body mass index compared with the control group [Pooyandjoo et al. Obes Rev 2016].
In addition, it has been shown that a shift to soy foods as a major part of one's diet can produce - besides the anticancer / anti-recurrence benefits I have already documented in another Note here - significantly decreases serum total cholesterol and low-density lipoprotein (LDL) cholesterol concentrations, and in fact had a greater effect on reducing body fat percentage than traditional low-calorie diets [Liao et al, Nutrition 2007; among others]. Many forms of soy foods are available (soybeans, miso, tempeh, and even as simple as Soymilk.
3. Soluble High Viscosity Fiber Glucomannan
(from the tubers of Amorphophallus konjac) is a source of high viscosity soluble dietary fiber has been used for weight loss with positive results in adults, and although evidence is not wholly decisive, it may be worth a trial, as it appears to benefit by increasing satiety between meals (dosing is usually 2000 mg/daily, divided across three in-between meals doses, each with a full glass of fluid), and hence decreasing hunger and urge to eat.
It is well established that self-monitoring, in the form both of daily morning weighing and of recording daily intakes via a food records (manual or in an app) is a useful tool in any weight loss program, providing feedback and allowing for modulation of goals during the program.
Given that excess weight (obesity, and overweight status) is one of our major big-four preventable KILLERS, that include smoking (including second- and third-hand smoke)), alcohol (at ANY levels except sporadic and celebratory), and inactivity (including insufficient aerobic AND resistance/strength exercise/training), there must be a global initiative to reverse the trend toward what's become known as the "diabesity" epidemic, and best weighted forward projections suggest that even a modest reduction in any of these four killers could on its own more than halve all cancers and heart disease within a decade - more than any forseeable advances in chemotherapy, endocrine therapy, biological therapy, and immunotherapy - while progress in ALL of these could represent the greatest societal benefit we can bequeath both to ourselves, and future generations.
Jim Morrison said it all:
"the time for hesitation's through"
Director, Medical Research, No Surrender Breast Cancer Foundation (NSBCF) Breast Cancer Reviewer, Current Oncology