SHR

There are many benefits to be gained from exercise and weight loss in the overweight-obese population, and both are commonly prescribed to achieve cardiometabolic health improvements. However, exercise for weight loss is an inefficient and unsustainable route for many individuals. Instead, exercise should be done for health while weight loss is achieved through dietary modifications. But which has a greater impact? The answer comes from the University of Copenhagen, Denmark who recently published additional data from the CUT-IT study where 64 overweight-obese out-patients (age 45-75 years) with coronary artery disease (CAD) were randomized to undergo 12 weeks of aerobic interval training (AIT) three times weekly or consume a low-energy diet (LED) for 8-10 weeks followed by 2-4 weeks of transition to a high-protein/low-glycemic index diet. The AIT protocol involved a 38 minute session beginning with a 10-minute moderate-intensity warm-up followed by high intensity interval training (85-90% of VO2peak, Borg scale 17–18) on...

Protein is arguably the most important macronutrient we eat, and all the protein we accrue within the body is in the form of muscle, organs, and countless of other essential compounds. In fact, the typical human cell is roughly one-fifth protein by mass. Unlike carbohydrates and fat, there is no storage form of protein on the body that sits around waiting to be used – every single amino acid plays an important role in our wellbeing. Although it may not necessarily be healthy, the body can survive indefinitely without carbohydrate intake and for a very long time with little to no fat intake. On the other hand, insufficient protein intake leads to rapid death. Generally speaking, all tissues in the body are under a state of constant remodeling via protein breakdown and synthesis. These processes are distinct physiological pathways (not simply the reverse of one-another) and their relationship can be referred...

Metabolically healthy obese – key protective factors Obesity is commonly accompanied by numerous comorbidities (metabolic syndrome) that involve insulin resistance (IR), type-2 diabetes (T2D), hypertension, dyslipidemia, cardiovascular diseases, and a systemic inflammatory state. However, not all obese adults have these conditions and there are in fact obese individuals who have less visceral fat and adverse health complications than would be expected, a condition that has been termed metabolically healthy obesity (MHO). Why are these people different? That is the central question answered by Goncalves et al, who reviewed the protective metabolic, genetic, and etiological factors of MHO that represent between 10% and 45% of the adult obese population. It turns out that everything is traceable to one seminal factor – lower visceral fat, which is what ultimately causes IR and the detrimental inflammatory and hormonal profile that contributes to increased risk for cardiovascular disease. Whether some individuals carry genetic predisposition to MHO,...

Individuals suffering from type-2 diabetes (T2D) can have a grocery list of health problems secondary to their condition, but the core issue is a dysregulation of glucose metabolism. The cause is multi-faceted and includes both genetic and environmental factors, but one consistently reappearing player is an excess amount of fat tissue – especially visceral fat. Therefore, it stands to reason that fat loss in individuals with T2D would lead to improvements in glucose metabolism. To test this hypothesis, researchers from the Mayo Clinic College of Medicine recruited 9 morbidly obese individuals with T2D (7 female) to follow a very low-calorie diet for 12-weeks. The diet consisted of 740 kcal daily for the first 4 weeks and 875 kcal daily thereafter, with meals derived from the Nutritional Guidelines for Bariatric Surgery. The participants met with a dietitian weekly and a behavioral psychologist every other week to facilitate compliance. Body composition measurements (DXA...

Smoking is associated with increased resting energy expenditure Cigarette smoking is known to be associated with lower bodyweight and weight gain is a common feature of smoking cessation. It is believed that nicotine acts by various mechanisms on the body’s energy balance and affects both the central nervous system and peripheral tissues by regulating the release of a wide range of neurotransmitters and hormones. Now, Blauw et al show in the first large-scale cohort of its kind that smokers have a 4.7% higher resting energy expenditure per kilogram of fat-free mass than never smokers. This result came from analysis of 1189 men and women from the Netherlands Epidemiology of Obesity (NEO) study. Where do we get our protein? According to Pasiakos et al from the US Army Research Institute of Environmental Medicine, who analyzed the NHANES 2007-2010 data on 10,977 adults, the average protein intake from animal, dairy, and plants was...

In 2012, researchers from Purdue University published a study suggesting that increasing total protein intake through whey protein supplementation was not effective in enhancing exercise-induced improvements in body composition and indices of metabolic syndrome in middle-aged overweight and obese adults. In this double-blind, randomized, placebo-controlled, community-based study, 220 inactive adults [about half of which had metabolic syndrome (MetS)] completed a 9-month resistance training (2 d/wk) and aerobic training (1 d/wk) exercise program that ultimately led to increases in whole-body strength and VO2max and an increase in lean-body mass (LBM) and reduction in fat mass (FM) despite no bodyweight change. However, during this intervention period, the participants were also instructed to consume a 200 kcal sachet twice daily with breakfast and lunch that contained 0, 10, 20, or 30 g whey protein (total daily supplemental dose 400 kcal and 0, 20, 40, and 60 g whey, respectively), which had no impact on...

Over the last decade, there has been a considerable amount of literature dedicated to clarifying the role that fructose plays in health and disease. Unlike glucose, fructose is primarily metabolized within the liver and bypasses a critical rate-limiting step (phosphofructokinase) in the energy production pathway of glucose. Bypassing this step means that the metabolism of fructose is less controlled than the metabolism of glucose, and this is the main reason why fructose and glucose have different metabolic effects. It has been shown in healthy adults that fructose stimulates DNL (de novo lipogenesis; the creation of fatty acids) to a greater extent than glucose, and this is the main reason why fructose has been portrayed as particularly harmful. However, isotopic tracer studies in humans suggest that 50% of ingested fructose is converted into glucose, 25% into lactate, at least 15% into liver glycogen, and only 10% oxidized directly or converted to fatty...

Energy restriction and weight loss lead to several fundamental changes in physiology that make weight regain easy and continued dieting more difficult. A lot of it comes down to the p-ratio of the dieting individuals, but one hormone that is central to the puzzle is leptin. That is because leptin levels decline both during dieting and after there is a return to caloric maintenance regardless of the weight-loss protocol. The suppression post-dieting is one aspect that makes maintaining a lower body weight so difficult. Interestingly, administration of exogenous leptin during this time has been shown to reverse the reduction in energy expenditure, the reduction in neuromuscular adaptations, and the increased food-reward cues. This begs the question, to what extent does leptin influences these changes? The answer comes from the work of Stefan Camps at Maastricht University, the Netherlands. He and his colleagues recruited 82 obese but otherwise healthy middle-aged men and...

Let there be no ambiguity, I do not agree with every aspect of the paleo diet. But this does not mean that I am against it. I believe that the paleo diet lays out very simple guidelines that virtually any person can follow with ease, and this in turn serves as an excellent starting point – “blank slate” or “template” if you will – from which a person can experiment and find what works best for their individuality. There is certainly no shortage of anecdotal testimonials to support the notion that “switching to” a paleo diet benefits health and wellbeing, but many of the claims are incredibly hyperbolic and there is literally no way for anyone to know if this was owed to the paleo diet, per se. This is why research exists – to build and organize knowledge in the form of testable explanations and predictions. So what can we...