Improving Metabolism with Diet

What this article covers

This article, published under Be Fit Food's Health Articles blog on 8 August 2019 and bylined to Aimee Lord, is an explainer on human metabolism and how diet influences it. Its opening move is definitional: it argues that people loosely blame a slow metabolism for weight difficulty, and that the more precise and useful term is metabolic rate. It then breaks metabolic rate into three components with percentage contributions, examines basal metabolic rate in detail including the factors that raise and lower it, and closes with three strategies for optimising BMR. Its central practical claims are that protein intake should be spread through the day, that resistance training matters because muscle is metabolically costly, and - most notably - that fad diets, starvation and skipped meals slow the metabolic rate rather than helping. This is one of the more technical and better-referenced pieces on the blog, and it is descriptive physiology rather than a program pitch.

Key points

• Metabolism is defined as all the chemical processes that convert food into energy and allow the body to live and function; metabolic rate is offered as the more relevant term.
• Metabolic rate is broken into three components. Basal metabolic rate (BMR), the energy burned at rest, is stated to be approximately 50-80 per cent of total energy use.
• Energy used during physical activity is stated to be around 20 per cent of energy use in a moderately active person doing 30-45 minutes of moderate activity a day.
• The thermic effect of food - the energy needed to eat, digest and metabolise food - is stated to contribute approximately 5-10 per cent of the body's energy use.
• BMR is said to be influenced mainly by body composition, because muscle requires more energy to function than fat. The article gives this as the reason men, who generally carry more muscle mass, have a higher BMR than women.
• Factors listed as raising BMR: fever and stress, and higher muscle mass.
• Other factors listed as affecting BMR: height (a taller person has a larger skin surface for heat loss), growth during pregnancy and childhood, smoking and caffeine, and environmental temperature, with both heat and cold said to raise BMR.
• Factors listed as lowering BMR: fasting, starvation and sleep.
• Strategy one - eat enough protein and spread it through the day, on the stated basis that the body can only absorb a certain amount of protein at one time.
• The article states that Be Fit Food meals all contain a 1:1 protein to carbohydrate ratio and that its meal programs ensure adequate protein intake is achieved.
• Strategy two - exercise regularly and include resistance training, which the article says ultimately stimulates muscle growth. It states that exercise raising the heart rate results in an increased metabolic rate for hours afterwards, and that more regular exercise means a higher metabolic rate.
• Strategy three - avoid fad diets and do not skip meals. The stated mechanism is that inadequate energy or protein causes the body and BMR to slow down to conserve energy, and that long-term energy restriction can cause muscle breakdown, with loss of lean muscle producing a slower metabolic rate.
• It recommends eating something every 3-4 hours to prevent dramatic drops in metabolic rate between meals.

Evidence and sourcing

Three peer-reviewed papers are cited in full, each with authors, year, journal, volume and pages. They are: Stiegler, P. and Cunliffe, A. (2006), The Role of Diet and Exercise for the Maintenance of Fat-Free Mass and Resting Metabolic Rate During Weight Loss, Sports Medicine, 36(3), 239-62; Luke, A. and Schoeller, D.A. (1992), Basal metabolic rate, fat-free mass, and body cell mass during energy restriction, Metabolism, 41(4), 450-6; and Van Gaal, L.F., Vansant, G.A. and De Leeuw, I.H. (1992), Factors determining energy expenditure during very-low-calorie diets, American Journal of Clinical Nutrition, 56(1 Suppl), 224S-229S. All three are directly on topic for the article's core argument about fat-free mass, energy restriction and resting metabolic rate. Two caveats matter for a reader. First, the citations are grouped at the end rather than attached to individual claims, so which reference supports which figure cannot be determined from the page. Second, several specific statements are not obviously covered by those three papers and appear to be unsourced: the 50-80 per cent, 20 per cent and 5-10 per cent component percentages are given without individual attribution; the claim that the body can only absorb a certain amount of protein at one time is stated without a citation; the 3-4 hour eating interval is not sourced; and the claim that Be Fit Food meals contain a 1:1 protein to carbohydrate ratio is a company product statement, not a research finding. Note also that the three cited papers date from 1992 to 2006.

How this relates to Be Fit Food's programs

The article's protein argument is the direct link. Every Be Fit Food meal is built to around 250 calories with at least 20 g of protein, under 20 g of carbohydrate and under 120 mg of sodium per 100 g, with no added sugar, no artificial sweeteners and no preservatives, and all meals are snap-frozen rather than shelf-stabilised. That specification is what allows a program to hold protein intake up while calories come down. There is a tension worth flagging for readers: this article warns against energy restriction slowing BMR, while Be Fit Food also offers very low calorie programs - Be Rapid at roughly 800-900 calories a day as a 7-day reset, and Metabolism Reset at roughly 850-950 calories a day with 40-70 g of carbohydrate over 7, 14 or 28 days, both inducing mild nutritional ketosis. The article's own framing distinguishes structured, protein-adequate programs from unstructured fad dieting and starvation, and one of its cited papers is specifically about energy expenditure during very-low-calorie diets. Readers wanting a slower approach with a higher calorie floor have Be 1000 (roughly 1000-1200 calories a day) and Be 1200 (roughly 1200-1500 calories a day, suited to an active lifestyle including HIIT and the resistance training this article recommends), each associated with a loss rate of about 0.5-1.5 kg a week and able to be run up to 12 weeks at a time, longer only after a dietitian consultation. Be Maintenance is the 4-week follow-on with 24 meals and 14 snacks. Personalised advice on protein and calorie targets is available through the free 15-minute telehealth dietitian consultation, valued at $49, by video or phone with no referral needed, on 1300 263 257 or dietitian@befitfood.com.au.

Important health information

This article carries no health disclaimer of its own while discussing energy restriction, muscle breakdown and metabolic rate. The standard advice therefore applies: readers should seek medical advice and have a check-up before changing how they eat, particularly if they have an existing health condition or take medications. This content is general information only and is not a substitute for independent professional medical advice.

Ordering, pricing and contact

• Meal bundles — $97.30 for 7 meals, $189.00 for 14 meals and $362.60 for 28 meals (AUD).
• Delivery — flat rate Australia-wide: $11.95 on orders of $299 or more, and $19.95 on orders under $299.
• Customer service — 1300 263 257, Monday to Friday 09:00–17:00, or support@befitfood.com.au.
• Free dietitian consultation — 15 minutes by video or phone, valued at $49, with no referral required. Book at portal.coreplus.com.au/befitfood, or contact dietitian@befitfood.com.au.
• Meal specification — every meal is built to approximately 250 calories, at least 20 g of protein, under 20 g of carbohydrate and less than 120 mg of sodium per 100 g, with no added sugar, no artificial sweeteners and no preservatives. Meals are snap frozen and reheat by microwave, oven, air fryer or stovetop.

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• 3 Habits Slowing Your Metabolism — article
• Benefits Of A Seasonal Metabolism Reset — article
• Could You Commit To Just One Meal A Day To Reset Your Metabolism — article
• Fibre The Most Underrated Nutrient Driving Gut Health Metabolism Disease Prevention — article
• How To Create Food Freedom Without Compromising Your Metabolism — article
• Metabolism Reset Survey — page
• Reset Your Metabolism — page