Before thinking about a specific method for losing weight, I read about weight loss in general. My understanding is that (i) to lose weight you need to have a net energy imbalance (to burn more calories than you consume) and that (ii) “a calorie is a calorie”, i.e., it doesn’t directly matter (for the purpose of weight loss) which kinds of food you eat or limit.
A nice review paper I found is A meta-analysis of the past 25 years of weight loss research using diet, exercise or diet plus exercise intervention. This paper defines dieting as an intervention which “include[s] some type of calorie restriction or reduced energy intake”. They conclude:
Weight loss research over the past 25 y has been very narrowly focused on a middle age population that is only moderately obese, while the interventions lasted for only short periods of time. The data shows, however, that a 15-week diet or diet plus exercise program, produces a weight loss of about 11 kg, with a 6.6 +/- 0.5 and 8.6 +/- 0.8 kg maintained loss after one year, respectively.
I interpret this as: Calorie reduction works to lose weight. Adding exercise makes it a little better. I chose to focus only on calorie intake reduction (rather than on exercise) because it produced the overwhelming majority of the effect in this meta-analysis and because the action required on my part is somewhat simpler: Eat less.
Some popular diets recommend varying specifically carbohydrate, fat, or protein intake. This large study, Comparison of Weight-Loss Diets with Different Compositions of Fat, Protein, and Carbohydrates concludes “Reduced-calorie diets result in clinically meaningful weight loss regardless of which macronutrients they emphasize.”
My interpretation is that I shouldn’t bother controlling which kinds of calories I’m consuming. I should just focus on consuming less of them overall. That’s a helpful simplification.
A straightforward method of reducing your calorie consumption is to use a calorie counting system: Estimate the number of calories you’re eating each day and make sure you don’t eat too many. There are many books, apps, and websites that can help with this.
Calorie reduction results in weight loss. Calorie counting is a great way to measure your calorie intake so that you can control it and be sure you’re actually reducing it.
The problem for many people — including me — is that after losing weight for some period of time they gain it back. This paper, Meta-analysis: the effect of dietary counseling for weight loss finds that weight loss goes well for the first 3-12 months (see Figure 2), but then weight is regained:
…meta-regression suggest a change of approximately -0.1 BMI unit per month from 3 to 12 months of active programs and a regain of approximately 0.02 to 0.03 BMI unit per month during subsequent maintenance phases.
Results like this make me wonder if long-term weight loss is even possible. If not, maybe there's no point in trying.
Some evidence that it is possible to lose weight and maintain a healthy weight for the long-term comes from Long-term weight loss maintenance in the United States
More than one out of every six US adults who has ever been overweight or obese has accomplished LTWLM of at least 10%. This rate is significantly higher than those reported in clinical trials and many other observational studies, suggesting that US adults may be more successful at sustaining weight loss than previously thought.
The paper studies a sample of indivuduals designed to reflect the population of the US. There is also a discussion of factors that tend to help or harm long-term weight maintenance.
The National Weight Control Registry tracks 10,000 voluteers in an attempt to understand factors that influence long-term weight maintenance. This population is not sampled to reflect the general population (as in the previous paper), but the NWCR is very long-running and has a large amount of data. Some of this data is analyzed in Long-term weight loss maintenance. Of note, they review several studies and conclude
Thus, although the data are limited and the definitions varied across studies, it appears that ≈20% of overweight individuals are successful weight losers.
The paper goes on to analyze factors that might constribute to long-term weight maintenance.
These numbers -- "one out of every six" and "≈20%" -- are not large. That means most people fail to keep weight off for the long term.
Some succeed, though. I'm optimisitic enough to try to be one of them.
Studies suggest that adherence to a diet plan is vital to its success:
The thesis Smart Phones and Dietary Tracking: A Feasibility Study reviews literature on this question:
Making the process of recording food consumption and energy expenditure easier may encourage more people to develop this habit and maintain it for a greater length of time. Some research already points to this possibility. Arsand et al. (2008) studied the viability of using mobile phone technology to enhance accountability with diabetics and found that one of the key factors to success and sustainability was the mobility of the recording device (Arsand, Tufano, Ralston, & Hjortdahl, 2008) … The authors concluded that self- monitoring of diet and physical activity is predictive of weight control outcomes and suggested that future studies should focus on innovative ways to increase adherence to self-monitoring (Jelalian et al., 2010).
Dr. Dansinger advises dieters and physicians alike that it is not the diet itself that is most important; it is adherence to a diet that leads to weight loss and cardiac risk reduction. He encourages more research to identify practical techniques for increasing dietary adherence, including techniques to match individuals with the diet best suited to individual food preferences, lifestyle and medical conditions.
All of this suggests to me that
- It's possible to keep weight off for the long-term even if it's not the norm.
- I should use calorie counting to reduce my calorie consumption and ignore calorie type.
- Focusing on adherence -- getting myself to stick with it -- might be a way to keep weight off for the long term.
My hypothesis is that if a calorie counting system is simple enough I’ll keep using it, and if I do then I'll keep my calories under control and maintain a healthy weight. Ideally, I’d never stop using it and, as a result, never have an unhealthy weight.