Always hungry? Blame it on the insulin
Weight loss is more than just calories in and calories out.
From time to time most of us feel the urge to shed a few pounds but get confused by the vast array of different dieting options available to us. In this new book, author David Ludwig, professor of paediatrics and nutrition at Harvard Medical School in Boston, Massachusetts, describes his approach to losing weight.
Ludwig makes the claim that his regimen will reduce hunger and not only allow weight loss but lead to improvements in health. He dismisses the widely accepted ‘calories in, calories out’ theory, rightly arguing that body weight is tightly regulated by the brain. Although we can easily lose some initial weight by reducing calorie intake, the body soon ‘senses’ this loss and reduces the metabolic rate and energy expenditure.
Ludwig’s idea is not new and he is simply presenting the “fat cell model” or the insulin-carbohydrate model. The basic tenant of the fat cell model is that overeating does not make us fat but that the process of getting fat makes us overeat. In other words, hunger and overeating are a consequence of an underlying problem. Ludwig uses pregnancy to illustrate his point. The developing foetus does not grow because the mother overeats. She eats more because the foetus is growing. Ludwig argues that fat cells suck up the majority of calories that we consume, leaving the rest of the body needing even more calories to fulfil its energy demands, hence why we overeat. This theory explains why our traditional dieting model, i.e. a low calorie diet, serves only to exacerbate the problem because the calories we eat are mopped up by our fat cells, triggering a starvation response and forcing us to seek out more food.
The underlying problem in the fat cell model is overconsumption of refined carbohydrate. In other words, eating too much of the stuff we like such as crisps, cakes, chocolate bars etc. By overeating these foods, we spike our insulin levels which quickly removes glucose from the blood and makes us hungry sooner after eating, hence we are more likely to overeat. Ludwig presents some evidence from studies to support his claims, one of which shows how an Atkins-like, high fat, low carbohydrate (10%) diet resulted in more weight loss than higher (40–60%) carbohydrate diets as well as producing greater improvements in cardiovascular risk profiles. Participants in the low carbohydrate group were actually burning about 300 calories/day more than in the other groups. Although these results are impressive, other studies have shown that weight loss occurs early in those assigned to low carbohydrate diets but over time, the weight loss is broadly similar to other dietary approaches.
The book is divided into three sections. The first deals with the current problems generated through obesity and describes how the low fat policy in the 1990s meant that we were eating more carbohydrates and ultimately doomed to become obese. The second section is a bit of a muddle and it seems as if Ludwig had to plug a gap before the third section. This final section is long but does contain lots of recipes and advice on preparing for the new eating plan.
Rather than call the eating plan a low carbohydrate diet, Ludwig tries to refer to it as a low glycaemic diet, allowing carbohydrates but only from vegetables and some fruits. The book is also full of anecdotes from patients who have tried the diet. The final section deals with the “how to” and contains lots of meal plans and recipes.
One criticism of the book is that for all the research studies mentioned, it fails to reference the study conducted by Ludwig’s own group. This was an 18-month study that compared a low glycaemic diet (i.e. his diet) with a standard low-fat diet. The result: no difference in weight or fat loss between the two groups.
Overall, it is a good book for someone looking to try out a low carbohydrate diet and from personal experience, I can testify that it certainly works well. However, the book does essentially what any good diet book should do: it suggests that we eat real rather than processed food. But do we really need over 300 pages to tell us that?
Citation: The Pharmaceutical Journal DOI: 10.1211/PJ.2016.20200623
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