
Sigma Nutrition Radio
Discussions about the science of nutrition, dietetics and health. The podcast that educates through nuanced conversations, exploring evidence and cultivating critical thinking. Hosted by Danny Lennon.
Latest episodes

Mar 22, 2023 • 56min
#475: Is Food Addiction Real? – Charlotte Hardman, PhD
Links: Go to episode page Subscribe to Premium Sign-up for our free weekly email: The Sigma Synopsis Description: The idea of food addiction has gained a lot of attention in recent years, as obesity rates continue to rise around the world. Many people struggle with overeating and find it difficult to resist certain foods, leading to a cycle of guilt and shame. The concept of food addiction suggests that there may be a biological explanation for this behavior, and that certain foods may be especially “rewarding” to the brain, leading to a kind of addiction. To help look at the evidence in this area, our guest in this episode is Dr. Charlotte Hardman, who is a leading researcher in the field of appetite and obesity. Dr. Hardman’s research focuses on the psychological and biological processes that contribute to overeating and obesity. She is particularly interested in the concept of “food addiction,” which suggests that certain foods may be addictive and lead to compulsive overeating, similar to substance addiction. In this podcast, we will explore the latest research on food addiction with Dr. Hardman. We will delve into the evidence for and against the idea of food addiction, as well as discuss the potential implications for public health and policy. Join us as we explore this fascinating topic and learn more about the complex relationship between food and the brain.

Mar 17, 2023 • 27min
SNP15: AMA – Semaglutide, “Carni-nutrients”, Sweating From Caffeine, & More
Questions Answered in this AMA [00:03:01] Mechanisms that keeps weight stable over time? [00:11:52] Semaglutide: Game-changer? Weight regain? [00:30:42] How to further lower LDL-C? Can I avoid statins? [00:43:52] Glyphosate: A cause for concern in food? [00:48:30] High caffeine intake is making me sweat more. What’s going on? [00:55:16] Should I avoid non-organic meat? [01:00:08] Is there evidence on iron and zinc co-ingestion for anemia of prematurity? [01:03:09] “Carni-nutrients”: Can vegan diets cause brain issues due to lower choline, creatine and taurine? [01:12:10] Are energy drinks bad for us? [01:17:43] What are some resources for doctors and patients that simply explain obesity & treatments? This is an episode exclusive to Premium subscribers. To listen to the full episode you’ll need to subscribe. However, you can listen to a preview here.

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Mar 13, 2023 • 1h 23min
#474: Glucose Peaks & Variability – Is Lower Better?
Links: Go to episode page (with links & resources) Subscribe to Sigma Nutrition Premium Receive our free weekly email, The Sigma Synopsis About This Episode: Often claims are made recommending that people should aim to keep peaks in blood glucose low in terms of both magnitude and frequency. And while many claims about blood glucose “spikes” are incorrect or purposefully exaggerated to grab attention, there are some reasonable and interesting hypotheses put forward in relation to blood glucose variability and excursions. For example, interesting questions have been raised in relation to the impact of blood glucose excursions in seemingly normoglycemic and/or healthy people. In this episode, we look at three specific elements of this: average blood glucose, glucose variability, and glucose peaks. All in the context of people without prediabetes or type diabetes, who have typical blood glucose measures in the ‘normal’ range. Specifically, we look at three hypothesized recommendations made elsewhere: “The lower you average blood glucose (HbA1C) is better, even if already in normal range” “The more you can minimize glucose variability, the better.” “Minimizing the number of glucose “peaks” is important, even if they don’t meet the threshold for hyperglycemia” Can normoglycemic people benefit from further reducing these measures? Let’s take a look…

Mar 7, 2023 • 1h 13min
#473: Diet & Depression (What Do We Actually Know?) – Nicole Lippman-Barile, PhD
Links: Episode page (with more links) Subscribe to Premium Introduction Depression is a common disorder and is a leading cause of disability worldwide. Depression results from a complex interaction of social, psychological, and biological factors. Diet has been one area that has been suggested in playing a role; from potential for exacerbating symptoms to being a treatment. And while some associations have been noted, many claims far exceed what (little) evidence exists. Online it is common to see people claiming certain diets can treat depression or that certain foods will improve outcomes. However, does the evidence match such claims? In trials that have been published on diet-depression, there has been considerable media attention and fanfare around some results. For example, the SMILES trial published out of Australia. However, some have raised considerable concerns about the interpretation of such findings. In this episode, clinical psychologist Dr. Nicole Lippman-Barile is on the podcast to discuss what we currently know about diet and depression, what issues exist with current studies, and why many nutrition-mental health studies are being incorrently interpreted.

Feb 28, 2023 • 53min
#472: Compared To What? – Understanding Food Substitution Analysis & Adjustment Models
Links: Subscribe to Premium Go to this episode's page (with links) Live event: London - March 18th Receive 'Sigma Synopsis' emails Description: When thinking about the effect of eating or not eating a certain food or nutrient, we can’t consider this in isolation. Meaning, we need to evaluate the impact within the context of what such an inclusion/exclusion does to an individual’s overall diet pattern. Thinking about this concept, the phrase “compared to what?” has been colloquially used. And while this is an important idea, there has been some misapplication of this principle. In nutrition science, this is related to the concept of food or nutrient “substitution”. And this concept is crucial to understanding the issues that can arise in nutrition studies, particularly when it comes to single food analyses in nutritional epidemiology. This concept of substitution is quite intuitive in controlled feeding studies. However, it is not as obvious when considering nutrition epidemiology studies. As noted by Ibsen & Dahm (2022): “Whereas studying the effects of eating one food instead of another is typically explicit in interventional study designs, it is often implicit and sometimes hidden in analyses of observational studies.” However, in nutrition epidemiology substitution is still happening, but it typically emerges as a consequence of adjustment models. In nutritional epidemiology, it is essential to adjust for confounders. E.g., one vital adjustment is often for total calorie intake. However, when our exposure is a specific food/nutrient, we must think about confounding by other foods. So knowing what, and how, a study is adjusting for variables helps us interpret it better. In this episode, Dr. Alan Flanagan and Danny Lennon discuss these crucial ideas of food substitution, adjustment models, and “compared to what?”. Go to this episode's page (with links)

Feb 21, 2023 • 58min
#471: Salt & Bone Health – Is There Cause For Concern?
Links: Episode page Subscribe to Premium Live Event: London, UK Receive the Sigma Synopsis emails About This Episode: Does sodium lead to calcium losses? Do high-salt diets harm bone health? At what thresholds could there be an impact? Does any of this change our recommendations around salt/sodium intake? Thanks to Sigma Nutrition Premium subscriber Kate Wall for submitting a question in the member’s area that inspired this episode. Kate asks: “Salt can impact calcium excretion in the urine and it is said that a high salt diet can increase risk of osteoporosis as it draws calcium from the bone and excretes it. How much of an impact does dietary salt intake actually have on bone health and how high would salt intake have to be for this to be a concern? Obviously high salt intakes are not something to aim for in general, but just wondered if this was a mechanism that could remove meaningful amounts of calcium in a way that I should be advising around this in those that we work with as nutritional professionals. Thanks!” So in this episode, Danny and Alan look at some of the evidence in this area to see if there are impacts that have pragmatic implications for nutrition and medical professionals, as well as health-concious people.

Feb 14, 2023 • 10min
SNP14: Nutrition Coaching Roundtable (Helms, Huschtscha & Baker)
Links: Subscribe to Premium Episode page Description: Nutritionists, dietitians and other health & fitness professionals face many challenges when attempting to help their clients and in understanding what approaches are best in a given situations. There are often discussions around improving client adherence to dietary recommendations. However, sometimes we need to think deeper about this topic. Is there really just a tool to fix this? Or could the problem be the recommendations themselves? Similarly, while quantifying dietary intake in terms of calorie and macronutrient amounts can be useful in some cases, it’s clear that this isn’t the best approach in many cases. So for coaches aiming to help athletes or those with body composition goals, how do we use “non-tracking” approaches effectively? This episode brings you a roundtable discusssion between three accomplised and insightful nutrition professionals; Dr. Eric Helms, Dr. Zoya Huschtscha, and Mackenzie Baker. In the episode we discuss the above-mentioned topics and more.

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Feb 7, 2023 • 1h 11min
#470: Melatonin, Meal Timing & Glucose Tolerance
Links: Episode page Subscribe to Premium Live event in London, UK Description: Meal timing has been a popular, and at times controversial, topic of interest in nutrition. Despite much speculation over the years as to potential advantages to specific meal timing or meal frequencies, for many outcomes there seems to be little pragmatically meaningful difference. For example, when accounting for calorie and macronutrient intake, there is little to no effect of meal timing on body composition, blood pressure, and energy expenditure. However, just because there is little evidence for the importance of meal timing in relation to those outcomes, this should not be interpreted to mean there is no impact of meal timing on all health outcomes. One area where meal timing may be an important factor is in relation to glucose tolerance and glycaemic control. For example, it has been consistently shown that eating at ‘biological night’ leads to worse postprandial glucose responses. And this could be particularly important for those with insulin resistance, pre-diabetes or type 2 diabetes. Some of the most influential work in this area has been done by Marta Garaulet’s lab at the University of Murcia. One of the central aspects they have published on has been the interaction between food timing and melatonin levels, and how this in turn affects glucose tolerance and cardiometabolic markers. In this episode, Danny and Alan discuss the topic of meal timing and glucose tolerance, using a recent study from Garaulet et al. to highlight some important concepts.

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Jan 31, 2023 • 1h 18min
#469: Chrononutrition – New Findings & Updated Views
Research in the field of ‘chrononutrition’ has continued to grow in the past couple of years, with some important studies being published in recent times. Chrononutrition is a research area that looks at the relationship between temporal (time-related) eating patterns, circadian rhythms, and metabolic health. While past podcast episodes have covered various aspects of chrononutrition, the latest research has added important pieces to the puzzle and has lead to both Alan and Danny updated their views on certain sub-topics. In this episode, we look at recent research (including that from the Big Breakfast Project) and how understanding and conclusions from the field have shifted over time. Dr. Flanagan also gives some insight into the important chrono work published in the UK, which his dotoral work contributed to. Links: Episode page Subscribe to Premium Live event: London

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Jan 24, 2023 • 1h 34min
#468: High Sugar Intakes Without Excess Calories: Harmful or Benign?
There is almost universal agreement that excess added sugar in the diet is detrimental to health. However, much of this negative health impact clearly relates to the ability of high sugar intakes to drive excess calorie intake and fat accumulation, which cause health issues. But what about situtaions of where there is not a calorie surplus (hypercaloric diet) or weight gain? Some people claim that sugar is inherently damaging. While others push back and claim sugar is only a problem in the context of a hypercaloric diet. So which position is more accurate? What evidence do we have? In this episode, Dr. Alan Flanagan and Danny Lennon take a look at situations of eucaloric (or even hypocaloric) diets, and what impact sugar has. Specifically, they investigate: in a situation where someone is not overconsuming calories or gaining weight, what health impacts do added sugars have? And if there are these calorie-independent effects, at what thresholds do they occur? Links: Episode page (incl. all links) Live event: London, UK - March 2023