“You can’t teach an old dog new tricks.” Though highly debatable the general premise of this well-known and oft quoted cliché is that it is hard to break old habits and learn new ones. The same principle also applies to ideas. We have a tendency to hold onto old ideas and reject those that challenge our paradigm. Weight loss and calorie counting seems to be an old idea resistant to change for many despite new literature proving the idea to be both unscientific and ineffective. Sadly the most obese individuals are often those who staunchly hold onto the idea of calorie counting. Despite the frustration and failure calorie-counting produces the idea of consuming more calories while attempting to lose weight is a fearful idea. How many times have we discovered when reviewing patients’ diet diaries a trend revealing that the most obese individuals are consuming the fewest calories and meals? In an era where weight management is desperately needed in order to curtail the subsequent health challenges reeducating patients about the null relationship between calories and weight loss is vital.
Teaching patients the different and distinguishing metabolic impacts of protein fat and carbohydrate on weight management is vital in order to successfully help them let go of the old idea that calories reign in weight loss.
When speaking in terms of calories protein confers an equivalent amount of energy compared to carbohydrates yet influences metabolism and satiety to favor weight loss unlike carbohydrates. Protein is rarely burned for energy except in cases of energy deprivation. Instead amino acids have an anabolic effect and promote both the building and maintenance of lean body mass and resting energy expenditure shifting the body’s energy preference to adipose tissue. Patients must understand that lean muscle is metabolically demanding and that preserving or building lean mass is paramount for permanent weight loss. Most low calorie diets force the body to utilize protein stores for energy robbing the body of lean mass and reducing energy expenditure and metabolism. Fat loss is minimal when metabolic requirements are decreased leading to stalled weight loss goals or a frustrating yo-yo affect in which weight is lost and gained back once a normal caloric diet is resumed.
Protein consumption not only produces favorable outcomes for weight loss but also plays a significant role in long-term weight management. Dietary protein has been shown to produce higher levels of satiety compared to fats or carbohydrates on an equal calorie basis. This will not only curtail overeating but will curb the food cravings that may direct individuals to snack on weight-promoting carbohydrates. Additionally proteins stimulate diet-induced thermogenesis which promotes energy utilization. Finally protein protects the gut from microbiome imbalances which also contribute to sugar cravings and long-term weight gain.
In the past few decades fat has taken the biggest beating of any food group resulting in a misinformed population of obese individuals. The low-fat diet craze inevitably resulted in one of the largest spikes in obesity ever witnessed. The easy explanation for this phenomenon is that the fat previously found in foods was replaced by sugar in their low-fat or fat-free counterparts. Therefore sugar consumption increased drastically resulting in our present obesity epidemic. If dietary fat was the culprit in obesity this nation should have seen an obesity revival long ago. Not surprisingly results from a systematic review and meta analysis on the effect of low-fat diets versus other dietary interventions for weight loss did not support the effectiveness of low-fat diets for long-term weight loss.
Instead various studies observing the effects of ketogenic and Paleolithic dietary patterns on weight loss have revealed significant and long-term improvement. These dietary patterns are naturally high in proteins and fats and low in carbohydrates. Higher fat diets have a high satiety value similar to high protein diets and improved rate of fat oxidation. When combined with a lower carbohydrate intake a higher fat diet generates more free fatty acids which subsequently upregulates gluconeogenesis and triglyceride cycling both of which are energy demanding processes promoting energy utilization. Preliminary studies show low carb/high fat diets result in significantly lower serum insulin when compared to high carb/low fat diets which also exerts both short-term and long-term benefits on weight management.
In part 2 we will dive into the debate on carbohydrates and see how calories from carbohydrates contribute to weight management compared to calories derived from protein and fat.