Consistency:
Diet is defined as what is eaten and drunk habitually. The key word here is Habitual. Regardless of how or what you eat, it needs to be consistent to influence your health.
The Energy-Balance Model:
The most accepted, widely understood and evidence-based model of weight management is the Energy-Balance Model, or EBM. Essentially, your overall energy intake via food vs your overall energy usage (things that keep you alive + exercise and physical activity), determines whether you gain or lose weight over a given period. This boils down to simply calories in vs calories out. Some other models exist like the carbohydrate-insulin model, however there is little to no empirical evidence to support these (Hall et al., 2022).
Challenges of Long-Term Weight Loss:
Studies have shown that weight loss is immensely difficult to maintain. Yet nowadays, there are an infinite number of options in front of us for how to lose weight. Fad diets, guru trainers, meal replacements, juice cleanses.
So why don’t they work long-term?
A meta-analysis in 2007 trialled 8 different weight-loss strategies and documented weight change over a minimum of 1 year follow up (Franz et al., 2007).
This diagram is a perfect demonstration of “Yo-yo dieting” in practice and the consistent theme of weight coming off and back on again is clear. Firstly, we can see that advice alone does not achieve weight loss consistently. This means that if you really want to make a change, you need to be more organized than taking advice off the internet or even just tips from a professional. There needs to be a plan in place for YOUR situation that meets YOUR needs. Secondly, we can see that diet change alone yields a moderate weight loss of 4-6kg at the 48 months mark. This is important to acknowledge that energy intake is what drives weight loss. Intake less energy and the results will follow. Lastly, we see that exercise alone does not yield consistent weight loss at the 12-month mark, the best data we have right now. Why is this? We will dive deeper into this in the exercise section…
Impact of Genetics and Metabolism:
You may be asking here, do genetics matter? Do I have a slower metabolism than others? There is some evidence showing certain genes, like the FTO region, have been associated with increased fat mass and higher BMI. However, when people with this gene participate in a controlled diet and/or exercise routine, they have been shown to display even better weight loss results than those without the predisposing genes (Mitchell et al., 2010)!
Metabolism is a legitimate factor in weight loss, and people suffering from hypothyroidism should seek help from their GP with weight loss. However, for the vast majority of people metabolic rate is a small cog in a large engine and does not explain why their weight management is poor or effective.
More in this series:
