Here is a recap of some of the most interesting stories in science and health that we’ve been reading and discussing over the past week – focusing on regulation of body fat and blood sugar.
First, a group of Japanese researchers demonstrated how circadian misalignment, caused by shifted feeding patterns, can wreak metabolic havoc. Perhaps more importantly, they uncovered what precisely is happening inside of the brain and body to at least partially cause this.
Next, we look at an English study, which revealed a way to that we might be able to put diabetes in remission – without drugs.
Finally, we all know that losing weight is hard, and keeping it off can be even harder. Does the struggle ever get easier? This experiment determined that if you keep the weight off for a year, your body adjusts to help you maintain the new weight.
Eating at the wrong time throws the biological clock out of sync – leading to overconsumption and metabolic derangement
As we’ve alluded to in a prior blog post, research suggests that when you eat can make a surprisingly big difference in metabolic health. Feeding behavior is a critical signal for circadian rhythms in animals. Specifically, eating late at night (when you typically sleep) – a time when we are evolutionarily adapted to be inactive – has been shown in a number of studies to be associated with varying degrees of metabolic derangement.
A team of researchers in Japan wanted to get a closer look at the underlying biological mechanisms for this observation.
In a recent experiment, they fed two groups of mice a high-fat high-sucrose diet. This was intended to induce a metabolic state similar to diabetes and obesity in humans.
One group of mice was fed this diet only during their regular sleeping time; the other group was fed the rich food when they would be awake and active.
The investigators measured and compared a number of different variables between the two groups. They found that the mice that were fed during the inactive phase voluntarily ate about 10% more, and weighed about 10% more than their counterparts. Not totally surprising, given past research. But why?
The likely reason for this difference was revealed in the blood work. It appears that feeding regimen changed the activity of genes related to the regulation of appetite in the brain – upregulating genes that stimulate appetite and downregulating genes that suppress appetite. Additionally, leptin levels were significantly higher, which in this context is suggestive of leptin resistance.
This lends further support to a larger body of work indicating that desynchronization of our biological clocks can lead to a cascade of deleterious metabolic effects. Based on past research, it seems plausible that similar physiological effects could be seen in humans who eat when they would typically be asleep.
A very low-calorie diet may reverse type 2 diabetes
Changes in our environment and behavior – including circadian misalignment – have contributed to an explosion in the rates of obesity and diabetes.
Intriguingly, there have been a number of trials that have shown that adopting a very-low-calorie diet can restore normal blood sugar control in diabetics. Bariatric surgery sometimes does this as well.
What we haven’t known, up to this point, is whether this effect lasts over the long term. A team of researchers in England sought to answer this question.
In the study, thirty participants adhered to a very low-calorie milkshake diet (around 700 calories a day) for eight weeks. An assortment of clinical biomarkers relevant to diabetes management, such as insulin sensitivity and glucose control, were measured at baseline.
After six months of maintaining this weight loss, these biomarkers were quantified again for comparison. Amazingly, at the six-month mark, 40% of participants were found to have recovered the ability to secrete insulin at levels similar to that of a non-diabetic. They had sustained nearly normal blood sugar, even months after the initial weight loss.
Why does this work?
The researchers speculate that fat cells, which accumulate in the pancreas, tend to block insulin secretion. When put on the low-calorie diet, the body burns up that fat, which restores the insulin-generating cells in the pancreas to their normal function.
Type 2 diabetes has long been regarded as a chronic condition with no cure. But these findings suggest that type 2 diabetes may indeed be reversible for at least some individuals – provided they are able to lose weight and keep it off.
It gets easier to keep the weight off – after one year
Weight loss can result in a number of exciting health benefits as the prior study illustrates. But research has shown that maintaining weight loss over time is a unique challenge.
Anyone who has ever dieted probably realizes this. The body “fights” weight loss in a number of subtle ways. The rate of energy expenditure will tend to slow down, and hormones associated with appetite and motivation often shift in ways that make you hungrier and less satisfied by the food that you’re eating. This makes keeping the weight off over the long haul very tough.
The scientific literature remains unclear as to whether these metabolic adaptations are ever overcome. Does the body ever “accept” this new lighter body weight, from a physiological standpoint?
In this study, twenty healthy obese participants achieved a weight loss of 13% body mass through an 8-week calorie-restricted diet. Once the initial weight loss was achieved, the subjects successfully maintained that weight loss for one year.
The researchers measured plasma levels of various hormones that are associated with appetite in response to a 600 calorie meal. They performed this test at three different points: before weight loss, immediately after weight loss, and after the one year of weight maintenance.
Immediately after losing weight, certain hormone levels in response to the test meal were suggestive of what we might call a “famine” state. For example, ghrelin – a hormone associated with increased hunger – had risen significantly.
However, after one year of weight loss maintenance, most hormone levels in response to the meals had reverted closer to the levels that the investigators found prior to weight loss. This finding suggests that these appetite-modulating hormones – which seem to sabotage us at first after losing weight – can actually adjust to a new body weight set point in a way that supports a lower body mass.
This is incredibly encouraging news for those of us who are trying to lose weight and more importantly keep the weight off for years to come. It may become easier for you to maintain weight loss – so long as you are able to stick with it for at least a year.