How to Eat and Lose Weight (if that’s your goal)
Calories, keto, fasting and glucose spikes: what the evidence shows, with Dr Nicola Guess
Episode Introduction
Of all the topics in health, what you ‘should’ be eating, has got to be the one crowded with the most conflicting views and so much misinformation.
One week the advice is to count calories, the next calories are insignificant and it’s all about macros. Except not carbohydrates. Never carbohydrates, unless you are fibremaxxing, in which case, pile on the carbs, they’re good for you. You should be fasting, we all eat too much and too frequently, but not if you’re a woman. Then fasting is bad for you. Saturated fat is the devil. No, sugar is the ultimate fiend. The continuous flip-flopping of conflicting, yet seductive advice is exhausting. And much of it is of course targeted at and absorbed by women. It’s so common that I hear from frustrated women; I simply do not know what to eat anymore.
So with these women in mind, I sat down with academic dietitian, Dr Nicola Guess, to put the biggest diet claims to the test. We look at what the research actually shows on calories, keto, fasting, glucose spikes with continuous glucose monitors (CGMs), ultra-processed foods and menopause, and finish with her simple, practical and evidence based way to build your meals. For those of you that have been on a diet treadmill your entire lives, I hope that you come away with more clarity, and less fear around food.
Guest Bio
Dr Nicola Guess is an academic dietitian and nutrition scientist at the University of Oxford, registered as a dietitian in both the UK and the US. Her research focuses on how diet can prevent and manage type 2 diabetes, with particular expertise in glucose regulation, insulin resistance, fatty liver and cardiometabolic health. She holds a PhD from Imperial College London and a Master of Public Health from Florida International University. Alongside her research, she runs a clinical practice supporting people with cardiometabolic disease and glucose dysfunction, and writes about which nutrition claims hold up to scrutiny on her Substack, Dr Guess’s Blog.
What We Cover
02:47 Does a calorie deficit still work?
• The viral claim that your body simply burns 500 fewer calories, and what it gets right and wrong
• What actually helps you keep weight off once it has gone
06:03 Keto, insulin and the “fat-burning” theory
• The tightly controlled study that put the insulin hypothesis to the test
• Where ketones may genuinely help, from type 2 diabetes to Nicola’s own trial in treatment-resistant depression
19:15 Should you be afraid of carbohydrates?
• Why sweet potatoes and bananas deserve a place on your plate
• When a low-carb approach can still be the right fit for someone
23:13 Glucose monitors and the fear of spikes
• Why a reading of 7.8 on a CGM does not mean prediabetes
• How last night’s dinner or a spin class can change today’s numbers
32:31 Can a CGM help you lose weight?
• What the evidence says, and the problem with “dressing your carbs”
• One encouraging finding for people with type 2 diabetes
34:29 Ultra-processed foods and the snack aisle
• What the landmark ultra-processed food trial may really be telling us
• Does the texture of your crisps matter? Separating fact from fiction
42:40 Fibre maxxing
• Water, volume and why some foods fill you up for fewer calories
• How a high-fibre diet may change the calories your body absorbs
44:45 Fasting and meal timing
• A surprising finding about meal frequency and insulin
• Early eating windows, fasting days and longer fasts: who they suit
52:35 Menopause, metabolism and body shape
• Does your metabolism really slow down at menopause?
• The type of fibre that may help protect body composition
55:56 Nicola’s plate, and the myth she most wants to bust
• A simple template for lunch and dinner
• Why fear of additives may be getting in the way of healthy eating
What You Will Learn
• Does cutting calories actually work for weight loss?
• Why do I regain weight after a diet?
• Is the keto diet better than other diets for fat loss?
• Should people without diabetes wear a continuous glucose monitor?
• Are ultra-processed foods the reason we gain weight?
• Does eating more fibre help with weight loss?
• Does intermittent fasting work better than calorie counting?
• Does menopause slow down your metabolism?
• Why does weight move to the stomach during menopause?
• What should a healthy plate look like for weight loss?
Key Takeaways
• Keto, fasting and meal timing are all ways of eating less. The best approach is the one you can sustain.
• If you don’t have diabetes, there is no need to fear the glucose rise after fruit, sweet potato or oats on CGMs.
• A calorie deficit works for weight loss, but keeping the weight off depends on building muscle and choosing foods that keep you full.
Further Resources and Support
Evidence-based nutrition
• World Health Organization: Healthy diet: Global guidance on the foundations of a healthy diet.
• The Nutrition Source: Healthy Eating Plate: Harvard T.H. Chan School of Public Health’s visual guide to building balanced meals.
• British Dietetic Association: Food Fact Sheets: Free, dietitian-written fact sheets on fibre, protein, weight and more.
Finding a qualified dietitian
• International Confederation of Dietetic Associations: Links to national dietetic associations around the world.
• Academy of Nutrition and Dietetics: Find a Nutrition Expert: Directory of registered dietitians in the United States.
• Dietitians Australia: Find an Accredited Practising Dietitian: Directory of accredited dietitians in Australia.
Weight and obesity
• World Obesity Federation: Global organisation working to improve prevention and treatment of obesity.
• Obesity Action Coalition: Education, support and advocacy for people living with obesity.
Blood glucose and diabetes
• International Diabetes Federation: Global information on preventing and managing diabetes.
• Diabetes UK: Information on prediabetes, type 2 diabetes and blood glucose testing.
• American Diabetes Association: Resources on diabetes risk, diagnosis and healthy eating.
Menopause and midlife health
• International Menopause Society: Global, evidence-based information on menopause and midlife health.
• The Menopause Society: North American society offering patient resources and a practitioner directory.
• Australasian Menopause Society: Fact sheets and a directory of menopause practitioners in Australia and New Zealand.
• Women’s Health Concern: Patient arm of the British Menopause Society, with clear fact sheets.
Physical activity and strength
• World Health Organization: Physical activity: Global recommendations on activity, including muscle-strengthening exercise.
Support with food and eating
• National Alliance for Eating Disorders: Helpline, support groups and treatment referrals in the United States.
• Beat: UK eating disorder charity offering helplines and online support.
• Butterfly Foundation: Support for eating disorders and body image concerns in Australia.
Disclaimer: This episode and these show notes are for general information and education only and do not constitute medical advice. Always speak to your doctor, a registered dietitian or another qualified health professional before making changes to your diet, medication or exercise routine, particularly if you have diabetes, a heart condition, a history of disordered eating, or are pregnant or breastfeeding.
